Happy! centers on Nick Sax, a scummy corrupt ex-cop and hit man. After a hit goes bad and Sax is left gravely injured, he is suddenly able to see Happy, a cheerful little blue horse who won't give in to adversity, no matter what unpleasant obstacles are in the way. Days before Christmas, Sax teams up with the saccharine horse to save the life of a troubled kid and maybe find redemption amid the squalor of his city.