An FBI agent trains and handles agents who go under cover to solve crimes; Joe mourns the loss of one of his own as the dangers of the job become all too real.

Darnell and Heather go undercover to infiltrate a band of bank robbers making its way across the U.S.; Lily poses as a waitress to get the goods on a dirty judge in a case that gets personal for Joe.

Artie, Joe's friend, comes back into town, and offers Joe a business proposition. His plan is to dig a tunnel from a bookstore to the bank across the street right into the vault. Lily goes undercover as the bookstore owner to keep the customers distracted from what's going on in the basement with Joe and Bruno. Also, things get complicated when Joe's old flame shows up and wants to move in with him.

Joe and Lola use a dead body to weave a net for a known killer in order to find where he's buried the bodies; Darnell and Lily act as a couple on the rocks in order to create a diversion while the FBI plants a bug in a suspect's car.

Joe handles a ""black op"" for his FBI boss investigating the death of an FBI agent working undercover with the LAPD, investigating them for brutality under cover of the law. Darnell poses as a reporter, Lily as a medical student in the autopsy, and even Marcy returns to UC work as a funeral director.