At Magnus' place, Clary tells everyone that the Mortal Cup is hidden in her mother's deck of tarot cards. She thinks she has to find Dot in order to get to them. Magnus says that Valentine doesn't have the Cup yet, otherwise he'd be making shadowhunters and controlling demons.
Luke is healed and comes out to tell them the cards are in his desk at the precinct.
Simon apparently spent the night with Maureen at her place. As she talks about how wonderful the night before was, he hallucinates that she's really Clary. Once he realizes that she's not, he freaks out and bolts out of her place.
While Clary and Jace wait outside, Luke goes to the police station to retrieve the cards, but is accosted by an Internal Affairs cop who takes his gun and badge. He is under investigation for the Jade Wolf incident.
Izzy is in her bedroom. She puts a picture of Meliorn in a box and puts the box under her bed. When she leaves her room, she sees her dad banging on Alec's room. There is no answer. She tells him she'll do the reports the Clave is requiring.
At the police station, Luke is being questioned by the IA guy. He asks if Luke wants coffee. When he opens the door, Jace and Clary, having used invisibility runes, walk in. They dismantle the camera, and talk to Luke about what's going on and to go get the cards from his desk.
Izzy is working on the Institute computer when Alec walks in. He's spent the night with Magnus working on healing Luke, but he really had cocktails with him. Izzy wants him to be more open with her about his personal life. She tells him she broke up with Meliorn.
Jace and Clary are in a storage closet to try to get to Luke's desk. She has a plan. Captain Vargas is by Luke's desk when Clary storms in yelling at Jace. She learns that the cards are in the evidence room. She's claiming Jace is cheating on her. The cops won't let him near her. She finds out the information she needs and leaves.
Simon is watching Nosferatu at an outdoor coffee shop. He's worried he's becoming a vampire. He orders a coffee and a bage with extra garlic. He starts hallucinating that the French press is running over with blood. Then he bleeds at the mouth.
At the police station, the captain asks the IA guy for a list of everything from Luke's desk. When they enter the lobby where there's a canine unit, the dog starts barking uncontrollably at the captain.
Jace and Clary leave the station. Alec and Izzy are there to greet them.
Simon calls Clary, but Jace hangs up phone because he has a plan on how to get the Cup.
The IA guy lets Luke leave for the day. He goes to the captain's office and notices blood coming from a closet. The captain is dead. Luke is not a suspect for her death.
Simon's sister and mom talk to Simon. They tell him they got a call from Maureen and are worried that he's doing drugs. When the mom and sister argue, Simon gets frustrated and breaks his desk when he pounds on it. He's got super strength.
At the police station, Clary and Jace are in the elevator. Clary needs a nightvision rune. She tries to draw it, but asks for Jace's help. He cuddles her while he draws it.
Izzy and Alec steal an officer's keycard. They go to the electrical room and shut off the power.
Jace and Clary's nightvision works. They climb the elevator shaft and get to the evidence vault. They find the box and the cards, but Clary can't get the Cup out from the card.
They meet up with Alec and Izzy outside, but there are demons everywhere which are detected by the glowing ruby on Izzy's necklace. One is in the form on a grandma. Jace kills it.
The break into a power facility to try to go through tunnels to get to the Institute. Alec stays to hold off the demons while Clary and the others get to safety.
Simon is in his room, calling Clary again. No answer. He hallucinates that Camille is on his bed. He looks in a mirror and sees that his teeth have become vampire teeth, but it's another hallucination. He breaks the mirror.
In the tunnels, Clary stops running. Izzy scouts ahead so Jace and Clary can talk. Clary wants to thank him for everything he's done to help her.
They catch up with Izzy. Her necklace is throbbing again. Shax demons show up and one jumps on Jace's face. He gets it off and kills it. He tells everyone to split up. Clary runs down a tunnel, but is trapped. Three shax demons are chasing her. She pulls out the cup card and it starts glowing. She's able to pull out the cup and shakes it at the shax demons. They leave her alone.
She runs back to find Jace. A shapeshifter demon comes out who looks like Jace, she realizes it's a demon and kills it. Luke and Alec show up. Alec takes her to the Institute.
When she gets there she hugs Jace and they kiss as Alec looks on. He walks away in disgust. Izzy follows.
Simon breaks into the Hotel Dumort. He's looking for someone. Camille shows up and tells him that the vampire effects are temporary, that he'll turn back human soon. But, unfortunately for him, he came back to the Hotel. She attacks him.