Jess invites Paul (guest star Justin Long), a music teacher at her school on whom she always has had a crush, to the gang’s big Thanksgiving dinner at the loft, which naturally goes horribly awry.
After a series of strangulations in Boston, the BAU looks for an UnSub who likes to keep mementos of the victims, and the team wonders if a common link to the casualties could lead them to the culprit.
Mike's spooked when Molly's boss invites them to a party on Halloween, a holiday he dreads.
Team Scorpion goes undercover at a university to find a hacker who infiltrates the Federal Reserve and threatens to collapse the world economy.
Kevin attempts to help Nicky. Randall and Kate reflect on differing memories of their childhood.
