Kay D'Arcy

Rossi and the team present one of the longest-tenured serial killer cases to college students, and they take the class through a nearly 20-year chase for the murderer. Mackenzie Astin guest stars.

In the season finale, when Tessa joins a knitting circle, George is a little surprised by the age gap between Tessa and her new friends. Still reeling from his one-night stand, George decides to put pen to paper and writes a song dedicated to his muse. Meanwhile, newlyweds Malik (recurring guest star MAESTRO HARRELL) and Lisa can't seem to get along. Recurring guest stars include PARKER YOUNG as Ryan Shay and LINDSEY SHAW as June.

When Lisa decides to propose to Malik (recurring guest star MAESTRO HARRELL), Tessa isn't sure how to support her friend and turns to George for advice. After Lisa's proposal doesn't go as planned, Tessa steps up and is inspired to fight for Ryan (recurring guest star PARKER YOUNG). Meanwhile, George believes his girlfriend, Nora (recurring guest star NATASHA LEGGERO), might be rude to her employees.