The story begins on a small spaceship docking with a refueling station. On board are a group of four aliens, Bernard, Sandra, Desmond, and Julian. During a particularly tedious period of their stay at the station, the other three begin playing with the ship’s controls while Bernard is outside playing spaceball. They accidentally disconnect his part of the ship, leaving him stranded while they crash into a large blue planet close by (Earth).
An aimless young man, Johnny, is sent prison. He entrusts his beloved dog, Evie, to the care of his former lover and best friend, Frank. When he gets out of prison, he has to face difficulties at home. Added to this, is the fact that he may have to give up Evie to Frank.
The Mazarin Stone, a famous jewel, acts as a magnet for crime. Holmes investigates the latest and perhaps most curious episode in its adventures.