Tampica is a fictional Caribbean island, newly independent from Great Britain. At the new nation's first reception in Washington, DC, the wife of the new ambassador kills herself after getting drunk and making a fool of herself. Or did she?
After questions about her death arise, the ambassador is eager to find out what happened and to close the case. They don't want the DC police to be involved and they don't have their own crack detectives to ship up from the islands, so they decide it would be proper to have someone from Scotland Yard investigate. They ask for Inspector Henry Tibbett.
As Inspector Tibbett looks into the woman's death, he discovers that despite her sexually casual and fairly alcoholic past, she had been on her best behavior that night. She was not drunk, she was drugged. And she did not shoot herself, she was shot. Now all he has to do is discover who did it.
This involves a trip to Tampica. He and his wife spend a few days in the sun and the surf, allegedly on vacation, while he talks to locals and discretely gathers information. They must rush back to DC when he realizes that their hostess there is in grave danger from the killer. The killer has killed the ambassador's wife and an employee at the embassy and is about to strike again.
No, I'm not going to tell you who did it! What would be the point of reading the book then? It's a fairly short book, just a little over 200 pages, so if it sounds interesting, read it yourself!