"The Ghost and the Crystal Mace" is the sixth episode of the third season of the show Space Angel. It originally aired in 1964.
The episode opens with Scott McCloud, aka Space Angel, and his crew traveling through space in their ship, the Star Duster, when Crystal gets something on the radar, a radio signal that keeps fluctuating 15 to 20 degrees. So they get close to the origin of the strange signal to see if they can find out what's causing it. This signal is one of several that has been puzzling scientists and disrupting space communications for some time, which is why Scott and the crew are investigating it. They soon come across a strange planet, and soon get some strange and spooky audio on the speaker, creeping out almost everyone, save for Scott. They begin the landing sequence, and they can't see the ground when they land through the clouds that shroud the surface of the planet, which looks as spooky as it sounds. Finally they land, and Scott orders Crystal stays behind while he and Taurus investigate the surface, to Crystal's frustration. Taurus feels like they're being watched, and they are, because the planet is home to ghosts.
Meanwhile, Crystal is aboard the Star Duster managing her expenses, when suddenly a ghost materializes in the ship, startling Crystal. The ghost, supposedly the ghost of a child, explains that he snuck in when Crystal had the door open. Crystal asks the ghost who he, or it, is, but the little phantom can't seem know who or what he is, saying that nobody tells him anything. Soon, the ghost causes the Star Duster to launch, to Taurus and Scott's surprise. The ship then starts performing acrobatic maneuvers. And once it returns to the planet, Scott and Taurus barely manage to avoid getting hit as the ship heads back into space.
Crystal manages to get the ship under control, while Scott and Taurus are confronted by other ghosts, who are looking for one named Humphrey. Meanwhile, on the Star Duster, Crystal learns that the ghost aboard the ship is Humphrey, the very same one the ghosts on the surface are looking for. Humphrey then accidentally contacts the chief, while the chief thinks its a not so funny joke. Afterwards, Crystal tries to get the ship back to the ghost planet to both return Humphrey home and save Scott and Taurus. Meanwhile, the two men are put on trial for the accused crime of kidnapping, with the sentence of death, though Scott tries to talk he and Taurus out of it. Meanwhile, Crystal tries to land the Star Duster manually.
Scott soon makes a deal with the ghosts to get Humphrey back so they may be left in peace and leave the planet. Meanwhile, Humphrey plays the role of co-pilot and helps Crystal land the Star Duster safely. Soon, Scott and Taurus spot the Star Duster, and Humphrey and Crystal disembark. Turns out the ghost judge is Humphrey's grandfather, and soon, Scott tells the ghosts about the radio signals that keep jamming space communications. The judge reveals the whole reason for it is to prove that ghosts are real, since people on Earth don't believe in ghosts. So, the ghosts and the Star Duster crew come to an agreement; the humans spread the word about the existence of ghosts, and the ghosts stop sending out those eerie radio signals. And so, the Star Duster crew head home to spread the word.