Dylan and Lizzie investigate the murder of a successful businesswoman who attempted to prolong the lifespan of humans. Also, Dylan and Andy look to continue their adoption search, and Detective Ryan Stock from Nebraska arrives to hunt for a potential serial killer.

A Sweet 16 celebration turns into a crime scene when the birthday girl’s stepmother falls to her death and the guests and staff are put under a microscope by the NYPD. Also, Ryan finds a new lead in his investigation, and Lizzie receives some positive news at the precinct.

Dylan and Lizzie investigate the case of a prominent divorce lawyer who is found murdered in a bizarre ritual. Dylan and Andy hit a bump in their adoption process. Lizzie and Julian reach a tough point in their relationship. Ryan’s serial killer case escalates.