 Two mysterious seamen come from Alan Rogers  (Ralph Morgan) past to blackmail him as he seeks to locate his missing daughters. Ellery Queen (William Gargan) is called in by Stewart Cole (Edward Norris), Rogers  secretary. Queen goes to the estate and finds one daughter already there and the second one expected. When she arrives, it is Ellery s secretary Nikki Porter (Margaret Lindsay) posing as the daughter as Ellery had her intercept the real heiress after learning of a plot to swindle Rogers. The blackmailing seamen are killed at a waterfront cafe after getting the blackmail money, Rogers is suspected and Inspector Queen (Charley Grapewin) arrives to arrest him, but he is also found dead.