Leaving his erudite lecturing ways behind, Oxford don Ambrose Usher heads for a holiday on the Caribbean isle of Santanna--as guest of old chum Tom Heywood, a British Intelligence agent. But the expected idyll is short-lived-since someone's out to murder Heywood, with two failed attempts and then a successful kill. So Usher tries to sort out the suspects in Heywood's circle: Sue Lee, a pretty, bright, overage Chinese student at the local university; revolutionary Hans Vanderloo, who's in surprising cahoots with Herr Fisher, a reclusive German; professor Pierre Latimer; Texas millionaire J. J. McGregor, with his fortress castle and huge arms cache. And meanwhile the cop on the case, Dick Denver from Hong Kong, focuses instead on some local drug traffic. Muddled plotting, some purplish prose, an unsurprising conclusion, and a large cast that's only occasionally interesting: a slow-moving slog--for Ambrose Usher devotees only.