When a man dives into a swimming pool and never comes up, Philo Vance is called in on the case.
Warren William was one of the less interesting actors I've seen in the role, but he had to eradicate memories of William Powell and Basil Rathbone for starters. As it is, it's some of the other characters that make this one interesting; it's fun to see a young Lyle Talbot in the role of Dale Leland, Etienne Girardot is great as a fussy coroner, and Eugene Pallette steals the show as Sergeant Heath. This one also has a marked horror element, as the murder is believed (by certain people) to be the work of a mythical "dragon" that resides in the pool (hence the title), an explanation that comes a little closer to the truth than you might expect. It also doesn't waste time, as it runs around sixty-eight minutes. This is a fun entry in the series.