Wealthy businessman Nicholas Van Orton (Michael Douglas) is a die-hard workaholic who shuns public events and friendships to live his life alone. As a birthday present, his estranged brother Conrad (Sean Penn) returns and offers him the gift of a lifetime - registration to a Consumer Recreation Services (CRS) 'game' which he promises will change his life.

Throughout the " is it / isn't it a game " plot, things take a turn for the worse when Christine dupes Nicholas to steal his bank account info, his house is trashed and he is taken over the border and buried. He realises that 'The Game' is a genius, sinister scam - a cut above the usual Nigerian emails about an incarcerated filthy-rich businessman who wants to borrow your bank account details for the day.

He returns to the mansion, and takes out a loaded gun that was hidden away and untouched by the looters.  He makes amends with his ex-wife and then tracks down the CRS team at their headquarters and confronts some of the actors in the staff canteen. He takes Christine hostage to the roof of the building.
  There's a load of banging on the locked door - and Christine is genuinely worried that Nicholas found a loaded gun.  He demands answers - Christine tells him that in fact it is all a game, and people are waiting at the door with a cake.  Someone starts to take a chainsaw to the locked roof exit, they don't sound too friendly.
  Confused and in a frenzy, Nicholas takes aim and fires as the doors are opened to reveal the CRS team, not gunmen, with a cake. He shoots his brother Conrad in the chest by accident.

Full of remorse, he staggers to the edge of the roof and jumps. Falling through a glass ceiling he lands on a huge inflatable - and is welcomed to his own birthday party by friends and family with a glass of champagne.

Nicholas and Conrad have a tearful reunion, and Nic promises to go halves on the cost of The Game. Nicholas congratulates some more background CRS actors, but notices that Christine is leaving early. He chases after her to learn she is about to start another Game. Full of beans again, he wants to go with her on another adventure.