Son of Sam is a card game invented by a younger Oliver, based on his peculiar ability to spot people’s “tells.” Convinced that the killer is “artist-like,” Oliver and Charles grow suspicious of Mabel’s new friend Alice, who presents herself as an Oxford-educated artist from a wealthy family. To test her, Oliver brings Son of Sam to the party they’re attending. As the game begins, he rapidly reframes the gathering as a 1970s-themed scenario and narrows the room down to a tense three-way exchange between Oliver, Mabel, and Alice. The game stops being a simple pastime and becomes a way to turn suspicion into a performance, with Oliver effectively directing the room and forcing everyone into roles. By using play as a pressure device, he tries to make the “truth” surface through discomfort and confrontation rather than through evidence alone, showing how easily investigation can blur into accusation. Oliver accuses Alice of lying, and therefore of being the killer. Alice ultimately admits she is not from a rich family and did not study at Oxford, then leaves.