ACT welcomes the great Sir Alan Ayckbourn to direct this American premiere of his 2003 “comedy of dark intentions,” about a naïve young student who rescues an old man dressed as Father Christmas from a hit-and-run driver and brings him back to the London flat she shares with her sister. As he showers her with gifts in a manner beyond polite gratitude and she accepts them in a way that begins to alter her personality, they embark on a dangerously Faustian game of mutual fantasy. They play roles in which no act can be taken at face value, no one is quite who they seem, and no good deed goes entirely unpunished.