Neil (Martin Clunes) is a downtrodden London toy salesman who has lived his whole life in the shadow of his best friend, the debonair Gary (Michael Praed). Neil is engaged to wed the attractive but rather sour Hilary, who is one of Gary's 'cast-offs' and who is so keen to be a bride that she is marrying Neil against the wishes of her domineering and snobbish mother. During Neil's drunken stag night, Gary engineers the ultimate "harmless prank", although Gary's real motive is far more sinister. Neil is drugged, then helicoptered to a remote, desolate Scottish island and left, naked and penniless. Neil has three days to get back to London for his wedding - a task he must accomplish without Hilary's family finding out.