

TV-PG
S1 • E3 Sep 21, 1966 51m7.7
When the Enterprise attempts to penetrate a space barrier, it is damaged and creates a potentially worse problem. Two crew members, including Kirk's best friend, gain psionic powers that are growing exponentially. This leaves Captain Kirk with the difficult choice; either marooning them or killing before they get so powerful they lose their humanity and become truly dangerous.