Plot
The film opens with a family—George (Tim Roth), his wife Anne (Naomi Watts), their son Georgie (Devon Gearhart), and their dog—arriving at their lake house. Their next-door neighbor stops in to help launch the family's sailboat, accompanied by a young man, Paul (Michael Pitt), who he introduces as a friend. A short time later, another young man, Peter (Brady Corbet), also a "friend" of the neighbors, arrives to borrow eggs from Anne. The two men impose themselves into the family's house, bludgeoning the dog to death with George's golf club and damaging Anne's cell phone in the process. A frustrated Anne demands that the men leave, asking George to throw them out. After some uncertain hesitance, George moves to eject Paul and Peter; Paul breaks George's leg with the golf club and the two men take the family hostage. They force the family to participate in a number of sadistic games in order to stay alive.
Paul asks if the family wants to bet that they will be alive by 9 o'clock the next morning; he breaks the fourth wall by telling the audience in an aside that he and Peter will probably bet on the family being dead.[4] Between playing their games, the two men keep up a constant patter and Paul frequently ridicules Peter's weight and lack of intelligence. He tells a number of contradicting stories of Peter's past, though no definite explanation is ever presented as to the men's origins or motives. When some of the family's other neighbors arrive for a visit, Anne passes off Paul as a friend until the visitors leave. During a scuffle that night Georgie escapes to the house next door, but finds the family dead. He attempts to shoot the pursuing Paul with a shotgun, but the gun fails to go off. Paul returns him to the house, along with the gun. After a few more games, the men play a counting-out game between the family members. Georgie is selected, they shoot him, and leave.
George and Anne grieve for their loss, and resolve to survive. Anne flees the house while George, with a broken leg and arm, tries to repair the damaged phone, but fails to successfully contact the police. Anne attempts to find help, but eventually Peter and Paul reappear, capture her, and return to the house with Anne bound and gagged. Anne grabs the loaded shotgun and uses it to kill Peter. An enraged Paul uses the television remote control to rewind the events to just before Anne grabs the gun. The scene then plays out again, but this time Paul grabs the gun before Anne makes her move. They kill George and take Anne out the next morning in the family's boat. Around eight o'clock they casually throw the bound Anne into the water to drown, winning the bet. They dock at the house of the neighbors that had previously visited the family, request some eggs, thereby restarting their cycle of murder.

Happy Green Clover thought hard on 3:18 PM.