After Tennant passes her medical and psych evaluations, she's surprised to see Sam's conducting her final interview to clear her return to work. Also, when the team discovers a breach in the U.S. Marshal's database, Sam joins Tennant in Las Vegas to locate the hacker.

Following the crash of a prisoner transport plane, the NCIS team must find the convicts that escaped onto the island. Meanwhile, Sam Hanna and Tennant are tasked with locating a high-profile Russian prisoner known as "The Chemist".