This installment feels like one of the more improbable adventures in the “Charlie Chan” series. The story involves Charlie’s eldest son, referred to as "Lee" (played by Keye Luke), who is traveling to participate in the Berlin Olympic games. At the same time, a plane equipped with an experimental navigation system is strangely taken over, and Charlie follows the trail to Berlin, eventually boarding the “Hindenberg” in a rush to prevent the Nazis from acquiring this important technology. The narrative possesses a darker tone, featuring some truly frightening moments that are somewhat offset by "Lee’s" usual pursuit of attractive women, which leads him into considerable trouble with the antagonists! I didn't pick up on any of the hints—I was completely baffled until the very end, but honestly, that wasn’t a problem. The film moves along at a good pace, and the supporting actors do commendable work; this includes Allan “Rocky” Lane (who you might recognize from "Mr. Ed"!) and C. Henry Gordon, who makes another appearance as the underhanded "Hughes." There are some actual Olympic scenes included, and fortunately, "Lee" doesn't require his father to use the paddle this time around.

Source on TMDB