Moreton is the representative in Rome for a London insurance broker who deals at Lloyds of London.
Moreton's troubles begin with the appearance of Dr. Avicenna. "Some instinct of self-preservation should have warned me against Dr. Avicenna from the startÂ?how many times since have I cursed myself for getting so easily, so light-heartedly involved with him?"
Avicenna's proposal is for a gigantic insurance policy on a dissolute Italian prince, to include a clause insuring the prince against a kidnap ransom.
The subsequent events are marvellously exciting, intricate and funny.