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"You Don't Know Jack"
420-Mary Ann's throat slit.gif


Episode NumberProduction Code


Episode Information
Air date: May 1, 2015
Viewers: 4.22 million[1]
Written by: Sean Calder &
Michael Golamco
Directed by: Terrence O'Hara
Opening Quote: From Hell letter
Related Articles
Co-stars: Brenda Braxton as Brenda Braxton
Tim Becker as Reporter
Other Co-stars
Objects: Grimm Diaries
Witch's Hat
Images: Images
Transcript: Transcript
Episode Guide
Previous Episode:
"Iron Hans"
Next Episode:

"You Don't Know Jack" is the twentieth episode of Season 4 of Grimm and the eighty-sixth episode overall. It first aired on May 1, 2015 on NBC.

Press Release[]

A SERIES OF CONNECTED MURDERS LEAD EVERYONE TO THINK A COPYCAT IS ON THE LOOSE - GARCELLE BEAUVAIS AND NICO EVERS-SWINDELL GUEST STAR - A string of homicides have the press asking Captain Renard (Sasha Roiz) if a Jack the Ripper copycat has arrived in Portland. While dealing with the investigation, Nick (David Giuntoli), Hank (Russell Hornsby), Monroe (Silas Weir Mitchell) and Wu (Reggie Lee) deal with a situation they never expected. Meanwhile, Adalind (Claire Coffee) and Rosalee (Bree Turner) must work together on a last ditch attempt to fix Juliette's (Bitsie Tulloch) condition. Elsewhere, Juliette decides to help her new ally even if it means hurting those around her.


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Nick, Hank, Monroe, and Wu arrive at the burned trailer ("Iron Hans") and go inside where they find mostly everything burned. Nick opens the weapons cabinet and finds many weapons survived the fire. Monroe grabs the Siegbarste Gewehr out of the cabinet and is relieved to find that it is still in good condition. Wu finds a diary on the ground that is partially burned, but overall is okay. Monroe then suggests they take what's left to the spice shop.

Juliette arrives at her and Nick's house and writes an email to Kelly that says Nick is in trouble, and he may be killed if she doesn't come. Juliette makes note that the house is safe and sends the message.

Nick, Hank, Monroe, and Wu work on getting items out of the trailer, and Wu asks Nick if he is going to go after Juliette, and he responds, "What do you think?"

Juliette gets a response from Kelly saying that she is on her way. Juliette then deletes the evidence.

Elsewhere in Portland, two prostitutes, Heidi McDunnah and Mary Ann Casey, are on a street corner waiting for their next clients. Mary Ann compliments Heidi's new hair and says it's too cold. She woges and says it's much warmer now. A car pulls up, and Mary Ann tells Heidi she can take this one. Soon after Heidi leaves, a man walks up to Mary Ann, and she asks him what he is looking for. "Something a Kehrseite couldn't handle, what you really are," he tells her. Mary Ann woges and asks him if he means something like this. He tells her now she is beautiful, and she asks him if he has a special place to go. He tells her he has a "lovely spot," and they leave. They arrive to a big open area and the man says he thinks they should do it right there. Mary Ann doesn't like the idea of doing it on the ground and starts to leave, but the man grabs her arm, pulls her back, and slits her throat.

In the spice shop, Rosalee and Adalind work on the suppressant, and Rosalee asks how the suppressant should work. Adalind tells her she doesn't know how it works and that she just knows it should work. Rosalee gets a little upset about Adalind saying the suppressant "should" work instead of being more sure. She tells Rosalee she doesn't do this kind of thing all the time and then tells her she was perfectly happy until Nick's aunt came to town. Adalind realizes it doesn't matter what she says since everyone hates her anyway. Adalind tells Rosalee that she trusted her when she was staying with her and Monroe ("The Law of Sacrifice") ("Nobody Knows the Trubel I've Seen") and she thought she was trying to help her. Rosalee tells her she doesn't feel good about what they did, but it was necessary to protect Diana. Rosalee then asks what's left for the suppressant, and Adalind tells her just her mother. The guys arrive with items from the trailer and tell Rosalee and Adalind what Juliette did. Nick tells Adalind they need to get her some place safe, so everyone tries to decide where the last place Juliette would look would be.

Nick and Hank take Adalind to Bud's house since his wife and kids are out of town. Nick introduces Bud and Adalind, and Nick tells Bud nobody can know that she is there. Bud is then caught up on recent events with Adalind and Nick expecting a child and Nick and Juliette's breakup. Nick tells Bud not to tell Juliette anything if she contacts him and Hank tells Bud that Juliette wants Adalind dead.

Juliette informs Kenneth that Kelly believes Nick is in danger and is on her way. Juliette tells him not to underestimate Kelly, and he says he doesn't and tells Juliette he doesn't underestimate her either. Juliette turns around to leave, but Kenneth tells her that he'd prefer she'd stay and that there is an open room for her. Juliette states that he doesn't think Adalind is coming back, and Kenneth says he doesn't see why she would. He says Nick is probably taking good care of her now that he knows he's going to be a dad. Kenneth notices an ash mark on the back of Juliette's hand and asks, "Been burning some bridges?" Juliette tells him it was a little payback, and he says there will be a lot of that.

Nick arrives home with his gun drawn. He searches to see if Juliette is there and notices ash marks on the computer mouse.

In a swimming pool, Captain Renard is face down and unconscious. He wakes up and panics before swimming to the edge of the pool.

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Nick and Hank meet Wu at the scene of Mary Ann's body and then go talk to Heidi, who found Mary Ann's body. They question her, and as she starts getting emotional, she briefly woges, so Nick tells her he is a Grimm. Nick asks her if Mary Ann was Wesen also, and she tells him she was a Fuchsbau. Nick and Hank ask a couple more questions, and then Wu has someone take Heidi home. The three of them go examine Mary Ann's body and see that her throat is slit. Nick then notices the wound on her stomach and says, "This is more than just a cut."

Monroe, Rosalee, Renard, and Adalind watch as Catherine Schade's casket is taken out of the ground. Before they leave, Adalind goes and tells her mother what has happened since she died and says that after she gets Diana back, she is going to raise both of her children the right way.

At the precinct, Hank does a background check on Mary Ann, and then Wu comes up to the detectives. He tells them that the M.E. report says that Mary Ann's uterus was skillfully removed using a sharp blade. Nick looks at the report and notices that it says the killer is likely left handed. Hank says the case is sounding familiar, and Nick asks if he is thinking Jack the Ripper. Nick then does an internet search on Jack the Ripper.

Nick, Hank, and Wu go to Renard in his office to tell him their theory that they could be dealing with a Jack the Ripper copycat. Hank says they haven't tied the killer to anymore victims yet, but they're doing a five state search. They leave the office, and Nick suggests the victims in the 1800's could have also been Wesen; Hank says it sounds like Jack the Ripper could have been a Grimm. Nick says he wishes they had the trailer and Hank says not everything got destroyed, so they could get lucky.

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At the spice shop, Adalind says she can't cut into her mother's body, so Rosalee takes over. Rosalee cuts out Catherine's liver and gallbladder, and Monroe puts them into the cauldron. Monroe pulls Catherine's mouth open and Rosalee cuts out her tongue. Rosalee then hands Monroe a chisel and hammer to crack Catherine's ribs so they can remove them, but before he can do anything, Nick and Hank arrive. He then goes to the basement with them to search the diaries.

Nick and Hank let Monroe know they're looking for something on Jack the Ripper or someone like him.

Heidi is waiting for a client when the killer walks up to her. He tells her he is looking for something a Kehrseite wouldn't understand, and she woges. He tells her his friends call him Jack and calls her by her name. She asks if she knows him, and he tells her he's been watching her. He notes she's been talking to the police, grabs her by the throat, and stabs her in the abdomen.

In the spice shop basement, Monroe finds some info about similar cases from the Luxembourg Peasant's Revolt in 1798. Based on the brutality of the killings, the Grimm who wrote the diary was curious if the killer was another Grimm, but Monroe says the rest of the page is burned off. He continues on to the next page where the diary says the Grimm confronted a soldier who was killing a Wesen prostitute and removing various organs for an unknown purpose. The Grimm cornered the soldier, who did not woge, although there was something in his eyes "as if the Devil himself had taken hold of him." The Grimm plunged his sword into the soldier, but the soldier just "smiled as if death meant nothing to him." Hank asks if this means the soldier is the killer, and Nick says, "Or something was making him do the killings."

Upstairs, Rosalee and Adalind grind the last rib, and Rosalee dumps the resulting powder into the cauldron. Nick, Hank, and Monroe come into the room and tell them what they found in the diaries. Nick says that according to the books, Jack the Ripper may have been around longer than people thought. Suddenly a smelly steam cloud rises out of the cauldron, and Rosalee notices Adalind is about to faint. Nick grabs her and helps her get to the bed. A little while later, a skull forms in the liquid in the cauldron, and Adalind says all they have to do now is strain it. Nick gets a call from Wu and and he puts him on speaker. Wu tells him Heidi's body was found, and the killer has the same M.O. Nick and Hank go to the scene. Rosalee then suggests to Monroe that since Nick "must be going crazy," they should contact Trubel, and he agrees.

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Heidi's body is uncovered so Nick and Hank can have a look, and Renard comes up to them to ask if they have any leads because the Mayor's office keeps calling him to asks what they're doing with the case. Nick says there are no leads they can share with the press, and Renard tells him to share it with him. Nick and Hank tell him about what they read in the diaries, and Renard agrees he isn't taking that to the press. Renard tells them that whoever is doing this is flesh and blood, so find him.

Rosalee holds the witch's hat upside down while Monroe pours the suppressant into it, and the liquid comes out of the top of the hat into a glass jar. Rosalee comments that it looks like water, and Adalind says it won't taste like it. Nick and Hank return, and Rosalee says now they just have to get Juliette to take it. Nick says Juliette will never take it if she thinks Adalind had anything to do with it, and Adalind says unless Juliette knows it works. Adalind says she'll take it first because she doesn't have a choice since Juliette will kill her if Juliette stays a Hexenbiest. Adalind then drinks some, and when she's done, Nick asks how she feels. She replies, "Like I just drank my mother." Adalind says she needs to sit down and tells everyone they better hold her down. Suddenly Adalind woges, and her head starts going back and forth like she's going through an exorcism. Her Hexenbiest spirit comes out for a few seconds before going back inside Adalind. Rosalee notices the jar with the suppressant is about to fall, and Monroe catches it just before it hits the ground. The skylight shatters, causing glass to fall to the ground. Adalind reverts back and passes out for a few seconds. When she wakes up, Adalind says she needs to sit up, and she does some tests to see if the suppressant worked. She tries to woge but only gets a small ripple across her face. She then tries to use telekinesis on a jar but has little luck.

Juliette sits down with Kenneth and goes over the setup of her and Nick's house, and also tells him who lives in the surrounding houses.

Adalind is in bed at Bud's house, and she tells Nick that she didn't know Juliette would turn into a Hexenbiest. She then asks Nick what will happen with their baby after the suppressant works for Juliette. Nick tells her no one will take her baby this time and leaves the room. Nick goes to the living room where Bud and Hank are. Bud asks what happens now, and Nick just tells him to keep Adalind there. Nick goes to leave, and Hank volunteers to stay behind just in case.

Nick calls Juliette, and she tells Kenneth, who is loading many guns with Verrat agents, but he tells her not to answer because "suffering is good for the soul." Nick leaves a message on her voice mail to tell her there is something that can help her, and then he throws the phone.

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Renard is talking to the press about the recent killings. After he is finished, he steps aside for the Mayor to speak. While the Mayor speaks, Renard's bullet wounds begin to bleed again. Renard abruptly leaves and heads to a locker room. He looks at his chest in the mirror and makes a call, saying he needs to see the person right away. Two officers come into the room, and Renard leaves.

Renard arrives at Henrietta's house, and he tells her about what's been happening with him recently. She has him sit down and asks if there have been any dreams. He says he keeps reliving the moment when he was shot, ("Blond Ambition") and when he wakes up, he dreams about something reaching for him. He tells her he keeps having blackouts and waking up in strange places. He tells her some of the places, and Henrietta realizes it's always around water. Renard asks if she can help, and she says she doesn't know and that it's going to take some time. Renard says he doesn't have time and leaves.

Nick arrives at the precinct as Hank is instructing some officers. Nick tells Hank about trying to contact Juliette with no luck as the phone rings. Nick answers, and it's Juliette, who has him on speaker with Kenneth nearby. Nick says they have a suppressant that will work and asks her to come to the spice shop, and she agrees to come.

Henrietta is looking through a book when someone comes into her house. She woges but gets her throat slit by Jack the Ripper.

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Juliette arrives at the spice shop, and Juliette asks how they figured out how to make the suppressant, and Hank tells her the books from the trailer. Nick tells her it will work, and Juliette says they would have had to try it on another Hexenbiest to make sure it works. Rosalee hands Nick the jar with the suppressant, and he hands it to Juliette. She then causes the spice shop to shake, and Nick tells her to stop. The shaking stops, and Juliette asks if it looks like she need anyone's help. She tosses the jar into the air, causing it to levitate, and Rosalee tries to grab it, but Juliette throws her against a shelf with her telekinetic abilities. The jar falls to the ground and breaks as Monroe woges. Juliette smacks him across the face, again with her telekinesis, and Hank draws his gun, but Juliette causes it to fly out of his hands. Juliette asks, "When are you all gonna learn that I like who I am?" Nick draws his gun and says they don't, and Juliette woges. She then makes Nick point his gun at Monroe and Rosalee. Monroe gets Rosalee out of the way, and Nick says he can't let go of his gun. Monroe freezes in fear as Nick's gun goes off.

Guest Stars[]


Non-Wesen Beings[]


Select Scene[]

Production Notes[]


  • Renard's bleeding and blackout side effects from his mother saving his life reoccur.
  • Bud meets Adalind for the first time.
  • The trailer is badly damaged, but not all of its contents have been destroyed; subsequently, the remaining items, including some of the Grimm diaries and weapons, are moved to the spice shop basement.
  • It is revealed that Lauren Castro did not succeed in her campaign to become the mayor of Portland.


  • The first female Klaustreich is seen.
  • The names of the sent and received emails on Nick and Juliette's computer are of writers and other crew members for the show.
  • The last names of the first two murder victims, McDunnah and Casey, both are of Irish Gaelic origin. "Jack" also sings an Irish folk song after he kills Henrietta.
  • The Irish folk song that Jack sings is a slight variation of the song "Some Say the Devil is Dead" by Derek Warfield, with the location in the song, Killarney, changed to Whitechapel; Whitechapel was the location of Jack the Ripper's murders in the late 1880s.
  • The title is a common American phrase meaning that the addressee knows nothing, or at least lacks any kind of evidence for their assertions.
  • Rachael Perrell Fosket, who portrays Heidi McDunnah, also portrayed Harmony in "The Good Shepherd" (as Rachel Perrell).


Episodes of Grimm

Season 1

"Pilot" • "Bears Will Be Bears" • "Beeware" • "Lonelyhearts" • "Danse Macabre" • "The Three Bad Wolves" • "Let Your Hair Down" • "Game Ogre" • "Of Mouse and Man" • "Organ Grinder" • "Tarantella" • "Last Grimm Standing" • "Three Coins in a Fuchsbau" • "Plumed Serpent" • "Island of Dreams" • "The Thing with Feathers" • "Love Sick" • "Cat and Mouse" • "Leave It to Beavers" • "Happily Ever Aftermath" • "Big Feet" • "Woman in Black"

Season 2

"Bad Teeth" • "The Kiss" • "Bad Moon Rising" • "Quill" • "The Good Shepherd" • "Over My Dead Body" • "The Bottle Imp" • "The Other Side" • "La Llorona" • "The Hour of Death" • "To Protect and Serve Man" • "Season of the Hexenbiest" • "Face Off" • "Natural Born Wesen" • "Mr. Sandman" • "Nameless" • "One Angry Fuchsbau" • "Volcanalis" • "Endangered" • "Kiss of the Muse" • "The Waking Dead" • "Goodnight, Sweet Grimm"

Season 3

"The Ungrateful Dead" • "PTZD" • "A Dish Best Served Cold" • "One Night Stand" • "El Cucuy" • "Stories We Tell Our Young" • "Cold Blooded" • "Twelve Days of Krampus" • "Red Menace" • "Eyes of the Beholder" • "The Good Soldier" • "The Wild Hunt" • "Revelation" • "Mommy Dearest" • "Once We Were Gods" • "The Show Must Go On" • "Synchronicity" • "The Law of Sacrifice" • "Nobody Knows the Trubel I've Seen" • "My Fair Wesen" • "The Inheritance" • "Blond Ambition"

Season 4

"Thanks for the Memories" • "Octopus Head" • "The Last Fight" • "Dyin' on a Prayer" • "Cry Luison" • "Highway of Tears" • "The Grimm Who Stole Christmas" • "Chupacabra" • "Wesenrein" • "Tribunal" • "Death Do Us Part" • "Maréchaussée" • "Trial by Fire" • "Bad Luck" • "Double Date" • "Heartbreaker" • "Hibernaculum" • "Mishipeshu" • "Iron Hans" • "You Don't Know Jack" • "Headache" • "Cry Havoc"

Season 5

"The Grimm Identity" • "Clear and Wesen Danger" • "Lost Boys" • "Maiden Quest" • "The Rat King" • "Wesen Nacht" • "Eve of Destruction" • "A Reptile Dysfunction" • "Star-Crossed" • "Map of the Seven Knights" • "Key Move" • "Into the Schwarzwald" • "Silence of the Slams" • "Lycanthropia" • "Skin Deep" • "The Believer" • "Inugami" • "Good to the Bone" • "The Taming of the Wu" • "Bad Night" • "Set Up" • "The Beginning of the End"

Season 6

"Fugitive" • "Trust Me Knot" • "Oh Captain, My Captain" • "El Cuegle" • "The Seven Year Itch" • "Breakfast in Bed" • "Blind Love" • "The Son Also Rises" • "Tree People" • "Blood Magic" • "Where the Wild Things Were" • "Zerstörer Shrugged" • "The End"