The episode opens with Liv wandering the apartment, checking out the fridge and getting caught sucking on hot sauce by Gilda. She asks where Liv has been sleeping and Liv tells her she's staying with her ex. Gilda throws some shade on their potential for the future and leaves.
In a parking garage, a man starts beating up a woman, but when she starts to get the better of him in the fight she's shot in the back by a second, unseen person. Her name is Regina Sumner, a wedding planner, according to the police, who show up to check out the body. Clive is late, and when he arrives, he knows the victim; they used to date. It was his gun that shot her.
At Max Rager, Gilda is upset that Vaughn isn't taking her concerns about Liv and Major seriously. The two bicker a bit, and then Vaughn gets called to the lab. They have a degenerated zombie, which they have on a treadmill with a brain in front of it. Using their new SuperMax drink, they manage to give the zombie the ability to move as fast as 10 miles an hour.
A cop who nobody likes has pulled the Sumner case, and between the gun and an angry voice mail telling Regina to leave him alone or else, he feels like he has an open-and-shut case against Babineaux. Later, Liv and Ravi were talking about the case; Liv decides to eat the brain so she can try to help Clive.
Bozzio comes into the morgue with a scrapbook that Sumner left at Bozzio's doorstep (she was the woman from last week's episode). It's a mostly fictionalized account of her relationship with Clive. They realize she was a crazy stalker and her brain is probably not going to be a great experience, which is borne out pretty quickly.
After Major falls asleep that night, Liv breaks into his phone and the next morning demands to know who Rita is. Major defends himself against the paranoia and Liv apologizes, explains and leaves for work.
In the bedroom, Major hides a device and some paperwork in a safe in his closet, but Liv comes back to see him, catches him and demands he open it. He says no, telling her to fight the brain, and she leaves.
At the police department, Liv and Ravi asks Clive for details of the relationship. Clive said he broke up with Regina because she had a police fetish and didn't seem to really care about him personally. Liv advocates for the crazy stalker because she's on her brain.
Before they leave the department, Ravi starts harassing Clive using Game of Thrones references -- something that they learned from Bozzio Clive is interested in (he doesn't want his coworkers knowing about his life).
They learn that Regina was suing a former client and go to talk to them, even though Clive warns them they can't be asking people questions becuase they'll all get in trouble. They ask a woman who owns a dry cleaners some questions, and her husband comes out to talk. Liv sees a vision that indicates Regina had an affair with him prior to the wedding, and before he leaves the laundromat, he puts on his police uniform.
In the vision, Liv had seen the cop throw a scrapbook just like Clive's over the edge of a bridge. On the bridge, lovers would put padlocks on the fence. Liv finds three identical padlocks, engraved with different initials, and starts trying to figure out who the third, unidentified suitor is.
At work, Liv has tracked down a vehicle with ties to the crime scene; it's owned by the police department, but they can't find out who's driving it. She goes online using her stalker brain skills and posts that the driver had a confrontation with a group of cyclists last week, and that they want to know if anyone sees it.
At home, Liv is looking for more information on Rita when Gilda comes in. When Liv tells Gilda all the things Major said about Rita being pathetic and desperate, she gets hurt and gently nudges Liv in the direction of punshing Major.
At the morgue, Clive comes down to bring Liv and Ravi lunch. While they're talking, the annoying cop who's investigating the case comes and accuses them of stealing evidence from his desk. They all deny it. Liv gets a text; she's got a hit on the black SUV, and she goes to break into it to find out who's driving it. She successfully gets inside but before she can find anything, she learns the unsurprising truth that breaking into a cop car is a terrible idea. She sneaks into the back seat while the driver comes and starts it up; he answers a call and it's Chief Walt Price. While he's talking, he overhears Liv in the back seat and pulls over to tell her she's in trouble.
At jail, Liv is worried about the repercussions of being in a group cell without access to brains. Later, Ravi comes to visit her, saying that there were two different blood types at the crime scene: one from Regina and another they can't identify. Later, in the cell, another prisoner is ranting and raving, and Liv is about to break. The next day, Major comes to see her. She's lost her stalker brains but she's starting to get very hungry and edgy, and she can't wait for the next day when she can post bail.
Early the next morning, just as she's starting to go full-on zombie because of her cellmate snoring, she makes bail. Ravi brings her a shake made with Regina brain. Liv had stolen a page from a scrapbook that proved the chief had an affair with Regina, and in it, he can see that Regina's original, unaltered photo featured him...and a unique engagement ring on Regina that Liv had previously seen on the woman who owns the dry cleaner.
At Max Rager, Major is helping Vaughn work out. When Vaughn hits a wall, he drinks some Super Max and gets a massive charge of adrenaline that lets him do way more than he should be able to...but when another person working out nearby annoys him, he lashes out with rage and throws a medicine ball at the man. He gives Major a couple of cans of Super Max to help with his night job.
When Liv and Ravi arrive at the dry cleaner, the owner's brother is there -- it's the man who we saw attack Regina at the start. He runs when they identify themselves. The two bring Karl and Uma, the brother and sister, in for interrogation. It turns out the plan wasn't to kill Regina at all, just to scare her and to get the ring back. Uma killed Regina because she thought Regina was going to kill her brother. Uma goes to confess, and tells Liv that every man cheats.
Behind a two-way mirror, Clive talks the chief into letting Liv and Ravi stay employed since they cracked the case and spared the police department embarrassment.
That night, Liv is trying to break into Major's safe. He catches her and, eventually, lets her in. The only thing in there is her engagement ring. They go to bed happy, but then he gets a text from Rita and Liv checks it. It's Gilda trying to engage him to come over and fool around, and she sends a sexy photo of her body (but not her face).