A chase through the woods results in a man being shot.
At home, Jane asks Angela if she's okay. Angela admits she is still worried about Jane's job and wishes he hadn't said the things she said. She's a mother -- she worries. Maura arrives, interrupting the conversation. She's been volunteering with Hope and is here to pick Jane up for the latest investigation. Jane promises this case isn't dangerous before she leaves.
Jane and Maura discuss Jane's job offer at the FBI Academy. Maura thinks the positives are that it's a lot less dangerous. Jane finds that idea boring and is unsure about it.
The shooting victim's valuables are still with him except for his cell phone. His apartment is clean except for a cell phone bill. A jumpy Nina traces the location of the cell phone and reluctantly admits to Frankie that her mother is coming to town. Her mother is not nice to her boyfriends.
The cell phone is a few miles away, next to another apparent body. This one is still alive, but barely. He also has a card in his pocket that says it's from a wedding. The photo is of him and Maura.
Maura explains that she and the second victim, Edward, were married for 24 hours before getting it annulled. She was not drunk. Jane protects her, saying that they need to stick to the case, not her personal life.
At home, Maura is upset to find out she is still married. Apparently, the lawyer had a heart attack before processing the annulment. She tells Jane the whole story. They were deeply in love but Edward's mother, Tilly, disliked Maura because she wasn't from a rich family. They got married in Vegas to spite Tilly, but Tilly would not allow Edward to move away with Maura to start medical school so they separated and that was for the best.
Jane interviews Tilly and her second husband, Noah. Tilly is defensive and assumes Maura is blaming Edward for the other guy's death to get revenge. Meanwhile, Angela runs into Joanne who says she didn't mean to break Angela and Ron up, and Nina tries to coach Frankie on how to talk to her mom and decides they should pretend not to date because he cracks a joke about his mother.
Maura insists Edward is innocent so Jane goes back to the park and finds buckshot, proving that Edward was shot while trying to help the victim. She goes to Edward's room but Tilly tries to throw her out and Edward refuses to talk to her.
Maura goes to talk to Edward, who still trusts her. He doesn't want to talk in front of Tilly, but later tells Maura there were irregularities in his dad's books that he had hired Michael, the forensic accountant who was killed, to investigate. Michael was murdered before he could tell Edward what he found. However, Edward has a copy of the documents he was investigating at his house.
Kent discovers that there is rust and steel laminate on the buckshot, meaning it came from a rare gun manufactured in 1912. Vince and Jane investigate who owns one.
Maura goes to Edward's house as his wife to find the documents but Tilly shows up with a gun and demands she turn them over to her. Jane calls and Maura puts her on speaker. Jane reveals that Noah owns a gun like the one used. Tilly says that makes sense. She agrees to help Maura.
Maura is on the phone with Jane when Noah pulls up and runs her car off the road. She is okay but he tries to shoot at her. Meanwhile, Ron shows up at the Dirty Robber and refuses to accept Angela's break up with him. Also, Nina's mother and Angela bond over the fact that their kids have stupid ideas about trying to deceive them, as Nina's mom has already caught on that Nina is dating Frankie.
Noah demands the papers or he will shoot Maura. Maura says if he shoots her the papers will fall with her and he will never get them. Noah says he is so rich he can buy his way out of trouble and confesses to murdering Michael. He is about to shoot Maura when Jane shows up and he is arrested.
Frankie has a good time with Nina's mom, which makes no sense to Nina. Her mom says she didn't interrogate Frankie because she actually likes him.
There is a surprise divorce party for Maura and Edward, who sign divorce papers and socialize. Jane and Maura agree that sometimes change is a good thing even though it's scary.