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. MI5 then persuades him to become a double agent. In the mayhem of a poisoned cocktail party, he pulls off the job with the help of the bewitching Mata (Annette Lynton) but ends up in a Chinese takeaway, persuaded by a meat cleaver to work again for the Chinese.