When zapped by a mysterious energy field, Kirk's longtime friend and fellow shipmate, Lt. Cmdr. Gary Mitchell (Gary Lockwood), begins developing telekinesis and other astounding superhuman powers. Power corrupts, however, and Mitchell soon sees the Enterprise and its crew as being as far beneath him as any insect. With no choice but to attempt marooning Mitchell on a nearby planet, Kirk finds that he must battle one-on-one with a former friend who is now a powerful being.
The famous second pilot for NBC features an admirable mix of action scenes, choices for the captain, and a contemplation on what an individual may do if given powers beyond what he was meant to have. Interestingly, Dr. Elizabeth Dehner (Sally Kellerman) offers the sole voice of initial curiosity in embracing this superbeing when everyone else harbors fear. All in all it's not a great hour of Trek, but it's a good one.