Jane and Weller go undercover as a world-class assassin couple to prevent deadly information from getting into the wrong hands. The intimate assignment draws them closer than ever. Meanwhile, David embarks on a solo mission to win Patterson back, and Carter clashes with Mayfair over how to handle a dangerous individual.

Jane reels from a series of massive revelations about her tattoos and grapples with whether to trust Oscar. Meanwhile, a tattoo leads the team to a shocking discovery in the Black Sea.