Shy librarian Alison Little arrives at a hotel to meet long-lost cousin Tom Cheyney. Eccentric, accident-prone Tom Chance turns up for a blind date with Alison Hughes but, due to misunderstanding, they end up with each other as Tom's clumsiness with a rowing oar knocks his date unconscious.

Alison's parents are not exactly warming to the notion of Tom after their daughter returns at three in the morning minus her dress. Tom returns it to her at the library but gets into a row with an aggressive Scotswoman who, due to another 'coincidence', believes he is the man who sold her son a duff car.

Tom believes he has had no post for six and a half weeks but in fact all his mail got stuck behind a heater and, as he has not paid his bills, tthe amenities are due to be cut off.

Tom is arranging a surprise birthday for Alison which includes a pillar box singing telegram that arrives seven hours early and an odd caterer who puts plastic insects in the food to spark off conversation.

Tom's bad luck affects Alison's visiting cousin Thomas.

Tom and Allison are now living together. On the day that Tom won a boat years ago—which was stolen the next day—it is returned by Corporal Browning, who drops in—literally.