A space ship lands on Moonbase Alpha and it contains several aliens in a state of suspended animation. The instruments of the Alpha personnel do not detect any life, so they attempt to open one of the chambers. This triggers the destruction of the person inside and the reanimation of the other aliens on the ship. Captain Zantor is the leader of the aliens and he informs Commander Koenig that they are but one of many ships sent by their home civilization to other worlds. Their mission was to orbit the Moon and determine if their physiology was compatible with humans. If they were compatible, then they were to make contact with Earth. If there was no compatibility, then they were to commit suicide. The occupants of Moonbase Alpha help Captain Zandor repair his ship and prepare for the continuation of their journey to Earth. Since there is now an empty suspended animation chamber, Zandor offers to allow one of the Alpha people to go with them to Earth. Koenig decides to have their computer select one person at random to return to Earth. However, Commissioner Simmons, the representative of Earth authority on Alpha and a man now having little to do, is desperate to return to Earth. He takes a weapon and forces Koenig to allow him to go. Unfortunately for him, Zandor is unable to adequately prepare the suspended animation chamber for his body and shortly after they leave, he awakes. The episode ends with him on a communicator begging Koenig to help him. There is nothing that Koenig can do, so Simmons will die of thirst, because the journey to Earth will take 75 years and he is sealed in a small chamber. While the special effects are now lacking in style, they were very good for the mid-seventies. What I find disturbing about this and many other episodes is that one person is so self-centered that they will risk the entire colony just to satisfy themselves. The people of Alpha were colonists, which had to be carefully selected for psychological stability. It is most unlikely that such people would be members of the colony. Other than that, the episode is fun to watch. It is a classic episode of television sci-fi that should be seen by all science fiction fans.