David, a young scientist investigating what happens to the brain during the process of learning, suddenly finds himself the subject of a bizarre experiment. On the way home from the lab one night he spies Tony, a fitness instructor from his gym, on the same platform waiting for the tube. David's had an obsession with Tony for weeks, but Tony's barely noticed him at all. Until now. When David imagines the man naked, an extraordinary thing happens: Tony strips there and then on the platform and offers himself in front of all onlookers. Horrified, David flees. But back at his flat, Tony reappears, as if by magic. And disappears, when David wishes him away. And reappears when he calls him back. David can conjure up anyone, from any time, and he does: Billie Holliday, Johnny Weismuller, Daffy Duck, Picasso, Sophia Loren, even his younger self. Mad with lust and losing all scientific objectivity, he runs the gamut of his fantasies until, sated and morally bankrupt, he's forced to confront himself. It is not a pretty sight.