S05E15: Over the Line

In the midst of working an undercover assignment, Crockett and Tubbs come across a clandestine vigilante group of frustrated law enforcement officers working within the department. Aware of Sonny and Rico's own frustration with how easily the bad guys seem to circumvent the law, the vigilante organization offers them an opportunity to join in. Lieutenant Castillo encourages them to accept the offer and work undercover in ferreting out the identities of everyone involved and to make sure that no one gets hurt. Unfortunately, that is too tall an order for his detectives to accomplish successfully.