The story of a harbor signalman who retrieves a suitcase full of money after witnessing a murder, fails to report it to the police, and finds himself the object of murderous and mercenary interest.

When the Government decide to build a Festival of Britain exhibition site, everything goes to plan, all except the fact that the main road and the pedestrian subway into the site, are blocked by a little corner shop, which is owned and run by a Mr. Lord and his family. When the Lords refuse to be bought off, and decline the compensation offered by the authorities. the police and the bailiffs try to evict them, only to come under fire from the family, who have barricaded themselves inside the shop.