A young man is brutally assaulted late at night on an Underground train by a gang of thugs. Beaten unconscious, he lies for days in a hospital bed - but appears to make a full recovery. On discharge from hospital, Carl picks up the threads of his daily life, visiting friends, seeing his girlfriend - until he starts to notice strange leaps in his perception of time, distortions in his experience. Is he truly reacting with the outside world, or might be be terribly mistaken? So begins a dark psychological drama that raises profound questions about the boundary between the real and the imagined.