The 8-episode series, based on an original pitch from Coates, follows two best friends, Judith (Waddingham) and Debbie (Spencer), who know everything about each other—or do they? Unbeknownst to Debbie, Judith has been living a double life as a highly trained assassin. When a hit goes horribly wrong, the pair must go on the run together and work to repair their broken friendship—all while being targeted by a mysterious enemy who wants them dead.