Spock commands a stranded shuttlecraft crew and discovers how difficult command by logic really is.
A shuttlecraft carrying Spock and several crew crash-lands on a planet with hostile giant creatures, while the Enterprise is under pressure to deliver medical supplies and cannot search for them. Spock must command, and his purely logical approach is tested by the fears and mistrust of the others.
The story explores the limits of logic and the difficulty of leadership. Spock is shown learning the value of a human gesture, and McCoy and Scotty's conflicts with him make for a lively tale. It also features the first shuttlecraft of the series, named Galileo.