At the end of the chaos of season two we left Marcella (Anna Friel) living under a bridge and presumed dead after having a complete mental breakdown. Season three sees her deep undercover having taken up Frank Young’s (Hugo Speer) offer of a new career. She’s worked her way into the sinister Northern Irish Maguire criminal family in the hopes of taking down their numerous operations. It won’t be easy though as Marcella’s mental state is extremely unstable, her former boss, Rav Sangha (Ray Panthaki) is investigating a linked crime and Frank’s reasons for investigating the Maguires aren’t completely professional.