Detectives Nick O'Malley and Kate Benson work in Special Unit 2, a secret precinct of the Chicago Police Department whose sole charge is to protect the city's citizens from Links, a malicious paranormal species that is the missing link between man and beast.

A 40-year-old bachelor gets his wish to be 17 again, and he goes back to high school where he romances the daughter of the woman he dated in high school the first time.