The Enterprise is ordered to clean up the aftermath of a doomed colony on Omicron Ceti III, a planet under constant irradiation from deadly Berthold Rays. Upon arrival, however, the colonists aren’t only alive but in perfect health, with no desire to leave their new world. They are in fact under the influence of plant spores which not only keep them in good and improved health but simultaneously keep them in a placid state of happiness and contentment. Mr Spock reacquaints with Leila Kalomi, an old friend who had been (and still is) in love with him. She leads Spock into being affected by the spores, and he is thereafter, for the first time, able to express love for her in return. Eventually the entire ship’s crew is affected, leaving Kirk alone to wonder how he can possibly rescue them from perpetual bliss.