When a man with multiple rat bites is thrown from a moving car, Danny works the case to find out why and who was trying to send a message.

A body discovered at a construction site follows the pattern of an executed serial killer.

CSI find a dead girl dressed as a mermaid tangled in the kelp off a ferry dock, and the case hits personally close to Lindsay when we discover she is also from Montana. The shooting death of a husband is grieved by two widows, and thrust our CSIs into the world of trinogamous relationships, where the chances of a jealous lover committing murder is multiplied by two. (TV-14)

Jackie's back in the swing of things. Zoey's working her first double shift and Jackie worries about her burning out. O'Hara accepts the title of ER chief. Kevin invites Eddie to a backyard barbecue to celebrate his new job.