When going into deep undercover, always be prepared for the worst.

Tribeca and Geils investigate a bank robbery, executed by a British gang, operating in the open, where everyone knows who they are. The group just hasn't been caught in the act. Both are sent deep undercover to infiltrate the gang and assist them with their next heist, ultimately to trap and catch them. Once the gang is caught and thrown in prison, the case is solved! Not! An important flash drive that was stolen from the bank is still missing, so the detectives must go back undercover. In prison.

Geils manages to outsmart the head of the gang, by suggesting that he hand over the flash drive. Simple. After turning it in to the Warden, Tribeca and Geils prep for their release. The only problem? The Warden accidentally intercoms their conversation over the whole prison yard, blowing their cover, and then plummets out of the window to his death, leaving them defenseless, stuck in prison with no way out.

Their only hope is the break themselves out and tunnel out of the cement walls. 

Meanwhile, Geils and Tribeca's sexual tension comes to a climax and their undeniable attraction is finally noted.