On her way to visit Egypt and its ancient past, Mabel Havelock stumbles upon a murder plot. Mabel is trapped on board a boat with a dead body and a boatload of suspects. And in the middle of the Nile River, a passenger disappears. Although language difficulties put her at odds with the lone police officer on board the boat. Mabel is determined to untangle the web of lies and deceit. She will have to use all her wits and ingenuity to solve the murder in the locked cabin.