Mortgage broker Eric Chase had a loving wife and a video game-addicted son before he was strangled to death in the parking lot outside his office. There's skin under his fingernails which means he fought back when he was attacked. Barry Ketchum is a regular attendee at AA meetings. He's been sober for one full year. He's also the man who murdered Eric Chase. The question is... why?
Barry wakes up in a hotel room. He's in bad shape after having fallen off the wagon. He wonders about the deep scratches on his arm until haunting memories of the night before come flooding back. Elsewhere, Angie and Oscar learn from Ronnie, the victim's wife, that her dead husband's ex-wife, Claudia, has cost them a lot in legal fees trying to get custody of her son, Chad. The ex's financial situation was never good, so custody went to Eric and Ronnie.
A witness provides a sketch of the possible killer. Someone named Tony called the victim's home the night he was murdered. The bartender where Barry got hammered refers to him as Tony when he stops by to wipe his prints off the payphone he used. Angie and Oscar pass by Barry as he makes a hasty exit. Neither got a good look at his face. Barry approaches Chad, who says he's not allowed to talk to strangers. The kid doesn't know this guy, but Barry knows his mom. Speaking of Claudia, she knows all about how cops work. She says, "When in doubt, blame the spouse."
Barry makes a speech at his AA meeting declaring that he fell off the wagon two days ago. He had told his family that he finally made it through a full year sober. They didn't care. He got angry. That's what drove him to kill Eric Chase during his bender. Oscar learns that a guy named Tony Denato, who was a low-level drug enforcer, came into the office looking for the victim a few days before he was killed. Ronnie doesn't recognize the sketch of the guy. Neither does Claudia, but she's not as believable.
Angie and Oscar learn that Tony Denato was the cover identity for Sergeant Barry Ketchum. He went undercover to bring down one of the largest drug operation on the east coast. Angie is ticked when she's told to take a vacation after her murder case is turned over to internal affairs. She decides to take matters into her own hands. Angie does take a few days off, but not for a vacation. She travels to Barry Ketchum's hometown to let him know that his name came up in a murder investigation. The sergeant gets rattled when Angie brings up Tony Denato. He uses the phrase "when in doubt blame the spouse." Angie's heard that phrase before.
Angie figures out the connection between Barry and the victim. Claudia Powell is his daughter. She's the one Barry called to say he was sober for a year. Claudia was still too hurt by all the pain he caused her. Barry tried to make things right with her by attempting to force Eric to back down on the custody battle. Things went south fast. Barry killed him in a drunken range. In present day, he pulls a gun on Angie ordering him to leave his daughter alone. It's a tense standoff in the middle of the police station. Barry ultimately points his gun away from Angie and towards himself. BANG! Angie is horrified as her suspect takes his own life.
Angie returns home to thank Oscar for having a chat with Manny. Her son has been asking about his father lately. Angie has been reluctant to reveal his identity. The events that transpired during her most recent case have caused her to have a change of heart. She gives Manny a big hug while letting him know that his dad's name is Mark Hanson. Manny has his eyes.