As chief greenfly sprayer to both the Chinese and Indian Embassies, the Optimist (Enn Reitel) is 'persuaded' to smuggle messages into the Russian and American Embassies via roller towels.

After losing money at the racecourse, the Optimist (Enn Reitel) meets Sal (Julia Chambers) the owner of the stables, and manages to get work as a stable boy, where he saves the aptly named horse Nutter from being sent to the knackers yard and lovingly prepares him for the big race.

Working as a humble cobbler, the Optimist (Enn Reitel) is thrown into an international world of crime and classical ballet when a diamond is stolen - the famous Light Fantastic.

On his arrival at a plush London casino, the Optimist (Enn Reitel) discovers that he has become an instant celebrity. What he doesn't know is that he is actually the identical double of the Boss who owns the club.

Whitewashing the walls and unintentionally the entire garden of a suburban home, mistaken identity causes the Optimist (Enn Reitel) to be hailed a new impressionist painter.

An unexpected inheritance leaves the Optimist with a crumbling and sinister country estate, which includes an equally crumbling and sinister butler named Old Norman (Eric Francis).