The night before Valentine’s Day, the rookies go out to dinner and happen upon Sgt. Grey and his wife having dinner. When Nolan arrests a man who is harassing a woman at the bar, Grey’s dinner is interrupted.
Grey’s wife encourages him to retire so they can spend more time together now that their daughter is headed to college, but he says he’s not done with the job yet.
Angela Chen and Wesley, the defense attorney, have continued to see one another and spend their first night together just before Valentine’s Day. Later, Wesley gets arrested for contempt of court. Angela asks him out for dinner on Valentine’s Day but he says he made plans.
While Wesley’s in lock-up, she checks his phone and sees he has “Dinner with Melanie” on his calendar. When she confronts him about it, he explains that Melanie is his step-mother. His dad died last year and this is her first Valentine’s Day alone. Angela feels horrible and Wesley’s upset that she violated his privacy.
Isabel is clean, is going through rehab and is working on making amends. She invites Bradford to visit her in rehab and he takes a personal day to do so. He’s thrilled that she looks so healthy. She tries to apologize for the thing she’s done but they realize that he may always see her as an addict, and she may always feel ashamed around him. They decide to end their marriage.
Officers West and Lopez interview an assault victim, Mr. Scott, with beginning dementia who was also hit on the head. He says he can’t remember who attacked him. Turns out there was another assault victim in the area. When they ask Mr. Scott about it, he claims not to remember but asks if “she” is alright. Lopez realizes that they never told him the other victim was a woman.
Lopez runs Mr. Scott’s DNA in the system. He is connected to many open homicide cases and may be a serial killer. At the hospital, Scott knocks Jackson and orderly out and tries to escape but Lopez takes him down and arrests him. Later, the male orderly hits on Jackson. Jackson returns with take-out for the two of them.
At the station, Bishop receives flowers for Valentine’s Day. Her “boyfriend” is married and will be spending the holiday with his wife. Lopez pushes her to break things off with him and she does.
Nolan saves a woman, Denise, who was electrocuted and she brings him a muffin basket to the front desk, which Chen is covering, and hits on him. Nolan turns her down but later, he and Bishop respond to a call about a break-in. It turns out Denise is the homeowner and she faked the emergency to see Nolan again. Her husband was killed overseas in the military and she’s very lonely. Nolan is sympathetic and tries to let her down easy.
Nolan throws an anti-Valentine’s Day party but only Ben and Lucy show up. Ben runs into a woman whom he invites to the party; it’s Denise. Denise sneaks into Nolan’s bedroom and overdoses on pills. They call an ambulance and when Nolan feels bad that Denise will be alone at the hospital, Lucy offers to go with her. Later, Bishop shows up at the party and hits it off with Ben, who is eager to share embarrassing stories about Nolan’s college years.