A birthday party is scheduled in the park, and everyone has interesting jobs to do. That is, everybody but Mordecai and Rigby, who are only trusted with the lame job of setting up the chairs. In order to prove they are not slackers, the duo agree to set them up without being distracted.
After an undercover cop working a narcotics-smuggling sting is shot dead, the killers next turn their sights on Boston homicide headquarters, leaving Jane, Maura and Frankie Jr. trapped in a fight for survival on their home turf. It's a situation that will force Maura to challenge herself like never before. On the home front, Jane's parents are excited that their oldest child, Tommy, is being released after serving time in prison.