 The Enterprise is ordered to Omicron Ceti III, believed to be under constant irradiation from deadly Berthold Rays, in order to evacuate all the colonists. Upon arrival, however, it seems that the colonists are in perfect health and furthermore have no desire to leave their home. They are in fact under the influence of plant spores which are keeping them in good health, and which simultaneously keep them in a placid state of happiness and contentment. Mr Spock meets Leilani, an old friend who had been in love with him. Spock is affected by the spores, and is for the first time able to express his love for her in return. Eventually the entire ship is affected, and Kirk is left alone trying to return his crew to sanity.