Agent Leroy Gibbs (Mark Harmon) and his team will have to work on a new case alongside the Federal Bureau of Investigation (FBI) in the upcoming episode of the long-running CBS series "NCIS."

In "Return to Sender," CarterMatt reports that Senior FBI Agent T.C. Fornell (Joe Spano) will return to see Gibbs and inform him about a huge problem. Two British prisoners have reportedly fled and sought refuge in the US. They managed to arrive undetected by hiding in a shipping container. One of the fugitive is a former spy. The authorities have to nab them before they can escape yet again.

An operation involving international fugitives such as this one requires very little to no mistakes. The NCIS and FBI will have to make sure that their every move is monitored and carefully executed. If they succeed, the British government will always be grateful for the help. If not, there will a lot of paperwork to explain why the joint forces of two top agencies were unable to apprehend a couple of criminals.

Last episode, Tony DiNozzo (Michael Weatherly) became a victim of identity theft. There were three fake Tonys running around the city, blackmailing senators, before the NCIS got wind of what was happening. Gibbs was informed that one of his members died in a car accident. Reports said it was DiNozzo, but when he got into headquarters, his agent was well and alive. The dead man was one of the bogus ones.

Upon further investigation, it was revealed that one of the masterminds was a woman who DiNozzo dated. She was in cahoots with one of the senator's secretaries. They had been asking the officials for money in exchange for their silence over their scandals.

"NCIS" season 13 episode 21 airs Tuesday, April 19 at 8 p.m. EDT on CBS.