In his last suspense novel (Running Scared, 1973) Burmeister lingered long over character motivation, and this backward unraveling of a mystery generated during the Spanish Civil War is also a tale of loyalty and betrayal. There are the two Americans who drifted into the International Brigade, gentle Jonathan and tight-lipped David; the Greek Christo, Jonathan's friend; the barefoot British aristocrat Marianne, Jonathan's mistress; the waif Carmen, David's inamorata; and Otto and Tom, who in the present -- when the story opens -- are organizing a yacht cruise. Ostensibly this is a holiday for Jonathan, just released from a British prison, but Christo and David know the plan is to hold a kangaroo court to try Jonathan as the traitor who had slipped military information to the Fascists years before. A serviceable story which picks up momentum toward the close, and the ""lost war"" background -- atrocities, partings, fevered camaraderie and doomsday statements -- animate even such familiar staples as the martyred Jonathan and the gallant Marianne. Fair to good.