Midnight, 1984. In a sprawling, run-down housing estate in south London, a man returning from a night out in the West End finds himself pursued by a strange hooded figure. So naturally when the Doctor and Romana arrive in the TARDIS the next day, they find themselves in the middle of a crime scene. But when child genius Matthew Pickles - inventor of a hugely popular handheld videogame - arrives to help them crack the case, they...