An otherwise Class M world targeted for a 23rd century agricultural colony until its primary, the periodical star Omicron Ceti, is found to emit fatal doses of Berthold radiation at that distance. The human colony survives, however, due to the insulating influence of a non-native spore plant whose side effects in humanoids include a inhibition release. A rescuing Enterprise landing party in 2267 also succumbs temporarily to the intense effect: Spock loses his Vulcan non-emotional veneer, and Kirk is ready to abandon his ship. Following the crew's recovery, the colony is evacuated.