Alonzo P. Tucker returns, this time more in character with the pirate that he originally pretended to be in The Sky Pirate. This time he and his crew of three dangerous aliens are searching for the buried treasure of an old interstellar pirate named Beelibones from the "Betelgeezy" (Betelguese) star system. Tucker has to find the treasure and protect the Robinsons from the three aliens. He searches for the treasure using a doodlebug that Dr. Smith has found.