The Robinsons meet a space traveler who turns out to be an Earth man, Alonzo P. Tucker, who was abducted from Punxsutawney, Pennsylvania, by aliens, in 1876. Tucker befriends Will by telling tall tales about being a pirate, but it turns out that he is only an ordinary man being pursued by aliens because he has stolen a mind reading device from them. Tucker returns the mind reading device to his alien pursuers, saving the Robinsons in the process.

Alonzo P. Tucker returns, this time more in keeping with the pirate character he tried to create in his first appearance. This time Tucker is searching for Billy Bones' treasure, and is using the head of Billy Bones, which is kept in a box, to help him find it. He has three cutthroats with him, and he has to find the treasure and keep the cutthroats from endangering the Robinsons. Tucker's robotic bird is back again, and continues to torment the robot.