Elizabeth Dehner

Captain Kirk takes the Enterprise into the galactic barrier, and the ship encounters strange activity that may be what did in the Valiant.

As electric charges strike the bridge, Gary Mitchell and Elizabeth Dehner are struck.

Mitchell's eyes glow silver, and he begins to exhibit unusual powers that grow by the hour.

His contempt for the mere mortals around him grows as well, and Kirk must decide whether to maroon his old friend on a barren rock or kill him while he still can.