The Man From The Sea

Description for THE MAN FROM THE SEA by Michael Innes:

When a man swims to shore from a freighter off the Scottish coast, he interrupts a midnight rendezvous between Richard Cranston and Lady Blair. Richard sees an obscure opportunity to regain his honour with the Blair family after he hears the swimmer's incredible tale of espionage, treason and looming death. But this mysterious man is not all he seems, and Richard is propelled into life threatening danger.