Dick Foran plays Bill Martin, an unemployed man who lives on the waterfront who inherits an old castle on a remote island. He gets the idea of charging boat rides to the island for a ghost & treasure hunt excursion, helped by his best friend Stuff Oliver(played by Fuzzy Knight) Peggy Moran plays heiress(and love interest) Wendy Creighton who goes to the island along with several others, where they encounter a caped and mysterious figure known as "The Phantom", who has half of a pirate treasure map, while Bill's associate The Captain has the other. Who will find it first, and survive the night, since someone is also a killer? Fun movie is oddly little-known, but amusing to think how this may have influenced "Scooby Doo, Where Are You?" since plot elements and characters are identical! A rushed production though, since this has a big goof: about 26 minutes in, as the group enters the library, a stage hand with portable spotlights can be clearly seen backing out of the scene!