Christine's brother Aaron dies after being hit by a car, and she presses for a murder investigation. When that doesn't happen, she infiltrates a group of street racers without authorization. Len and Ali investigate the death of an infant.

Len and Nicco work with a homicide detective to look into the connection between a cold murder case and the more recent murder of a gay-bashing thug at the same night club. Mickey uses a new computer program to find an arsonist.