One of Warner Oland's last appearances as Charlie Chan was this short and sweet mystery where Charlie happens to be involved in the smuggling of a diary intended to be used for blackmail. The blackmailer (Louise Henry) is all of sudden murdered and Chan must gather all the clues he can to find the killer. As it happens, he was on a cruise ship with the victim, and the diary somehow ended up in his trunk. This gets Number One Son (Keye Luke) involved, which of course, isn't a shining light in pop's eyes. "Does that mean I can go to?", Lee Chan asks his dad. "Unfortunately yes", Oland wryly replies, gathering up enough clues to prepare to uncover the killer amongst a list of sordid suspects (including J. Edward Bromberg, Donald Woods and Leon Ames) before they strike again. Even on their lowest budgets, the Chan mysteries always had some surprises, and this gives plenty of suspense as well before the culprit is named in the dramatic conclusion.