Everything goes wrong with 'The Great Brain Robbery' masterminded by Sid James' band of criminal comedians. Put behind bars for 15 years, the gang have one consolation - they hid their loot in a tree in the country before capture. But a dreadful shock awaits them after their release; the accommodating oak now stands in the backyard of a Police Station! Fate plays havoc with the crazy crooks attempts to retrieve their cash.