When ne'er-do-well Marty marries into the Irish mob, he knows he has to prove his worth to the family. So when his brothers-in-law tap him for a Christmas jewel heist disguised as Santa Claus, he sees his chance. But things spiral out of control at the office party as Marty loses track of his partners-in-crime and scrambles to escape the cops. An absurd case of mistaken identity and holiday hijinks ensues as this loser tries desperately not to end up on the naughty list.