Where We Left Off: Langston, driven to the edge by serial killer Nate Haskell, snaps and severely beats the killer before throwing him over a railing, killing him. Internal affairs questions Langston, with the episode ending before he can answer about the death of Haskell.

What's Next: Laurence Fishburne is off the show and Ted Danson joins the cast playing night-shift supervisor D.B. Russell. Marg Helgenberger will exit the series in January.

Season 12 premieres Wed., Sept. 21, 10PM ET on CBS