In 1975, children play hide and seek. Long after the party is over, one girl calls another's name, saying the game's done. She finds a body and screams.

In the present, Angela and Maura are determined to get Jane ready for her move to DC. Jane is overwhelmed and freaking out and the others won't stop crying.

At the murder scene, Vince knows the victim. His daughter was Vince's first girlfriend. Her sister Wendy was the girl murdered in 1975, when Vince was in high school. The case inspired him to be a cop. The victim, Walter, was apparently smothered and had an AA chip. Vince is upset that the family continues to suffer.

Vince reunites with his old flame, Mary, who confides in him that her family fell apart after her sister's death. Walter became an alcoholic and she and her mother moved away.   Then Walter sobered up and allowed work with a victim's advocacy group to consume him. Mary knows nothing of this work as it distressed her so he didn't talk to her about it.

The investigation shows an irate relative of a prisoner threatening the victim after a failed parole attempt. The relative claims not to have hurt the victim and has an alibi.

DNA shows father and daughter killed by the same person.

The investigation leads to the Davenport family, who hosted the party. Two older sons were constantly in trouble. The "good" son, Robbie, won't talk to the cops. The father now has dementia. 

Jane needs DNA evidence and goes to see the father, who thinks she is "Carol." She collects DNA from his tears.

It is determined Robbie is the criminal and he tries to run away in a helicopter but is arrested.

Meanwhile, Frankie struggles to get Nina a ring while she tries to win a honeymoon in a sweepstakes and Agent Davies appears and asks Jane out on a date. Jane at first says no then relents and the two end up having sex. And Maura's book is rejected by her editor so she decides to go to Paris to work on her second draft.