Willie Garvin has lost the will to live. He had worked for Modesty Blaise for six years in The Network, Modesty's criminal organisation, and rose to the position of her right-hand man and became her very best friend. Willie was on top of the world.

But then Modesty disbanded The Network and retired, and Willie didn't know what to do with himself. He got involved as a mercenary in a South American revolution, but his heart wasn't in it. He was captured and is now sitting in a primitive prison, waiting listlessly to be executed.

Fortunately, Sir Gerald Tarrant, head of a British secret service organisation, knows about Willie's situation, and he needs the services of Modesty and Willie for a very special mission. Sir Gerald visits Modesty and lays his cards on the table. Modesty is very grateful and agrees to help Sir Gerald as soon as she has rescued Willie.

This is the start of the adventure. Sir Gerald's job turns out to be a perilous intervention against the criminal mastermind Gabriel, who intends to steal a huge consignment of diamonds. The action starts in the south of France, where Willie causes Paco (who is on Gabriel's payroll) to lose his head (literally). Then it's on to Egypt, where Modesty and Willie get captured by Gabriel's gang. The diamond heist succeeds, and the action moves to a small island in the Mediterranean where Modesty has to vanquish the incredible Mrs. Fothergill in unarmed combat. But then all of Gabriel's gang are in pursuit, and there is nowhere to run.