While patrolling the Neutral Zone separating Federation space from the Romulan Empire, the Enterprise rescues the sole occupant of a small space ship damaged by a meteor swarm. To everyone's surprise, the rescued space traveler appears to be wealthy philanthropist Carter Winston, missing and presumed dead for the past five years.
It just so happens that Winston's fiancee, Ann Nored, is a security officer aboard the Enterprise. Upon their reunion, Winston tells her that he has changed since crash landing on the planet Vendor five years ago, and that he can't marry her. Just how much he's changed is soon revealed to the audience when he knocks out Captain Kirk and takes the captain's form. Winston, as Kirk, then goes to the bridge and orders helmsman Sulu to plot a new course that will take the Enterprise through the Neutral Zone.
It turns out that the being the Enterprise has taken aboard isn't Carter Winston at all, but a Vendorian, a member of a race of deceitful, shape-shifting aliens shunned by all decent races of the Federation, who had cared for the real Winston after he crashed on Vendor. An outcast among his own people, the Vendorian joined forces with the Romulans to lure the Enterprise into the Zone in violation of treaty so that the Romulans could capture her.
After a confrontation with Winston's fiancee, Ann, the Vendorian realizes that he has assumed not only Winston's shape, but his feelings for her as well. Having a change of heart, he saves the ship from Romulan attack by assuming the form of one of the ship's deflector shields. After the Romulan ships depart, he turns himself in to Captain Kirk. Although he will have to stand trial for his crimes, Kirk promises to put in a good word for him for ultimately saving the Enterprise.
This is the first episode of the animated Star Trek that was not written by someone previously associated with the live action series. James Schmerer is a prolific and adaptable television writer and producer whose credits include westerns (High Chaparral), crime dramas (Mannix, The Rookies, The Streets of San Francisco), and medical dramas (Medical Center). His science fiction/fantasy credentials include segments of Logan's Run, The Six Million Dollar Man, Isis, and Fantasy Island. "The Survivor" is his only work for the Star Trek franchise, although he would get the opportunity to again write for William Shatner when he authored an episode of T.J. Hooker in 1985.
Carter Winston is given voice by Ted Knight, who is best remembered as pompous jackass Ted Baxter of The Mary Tyler Moore Show. He had previously worked for Filmation as narrator of their early cartoons based on DC super-heroes and continued in that role for Hanna-Barbera on Super Friends. Despite the absence of Lt. Uhura from this episode, Nichele Nichols still has more than her share of lines as the voice of Winston's fiancee, Ann Nored.
The advantages of animation are on display in this episode in "Carter Winston's" native form. The Vendorian is a truly alien looking alien that, in the pre-CGI era of the early 1970's, would have been impossible to create in any other visual medium except perhaps comics.
The story is hardly startingly original, with elements of it bearing strong resemblances to original series episodes "The Man Trap," in which a shape shifting alien resembles McCoy's former lover, and "What Are Little Girls Made Of?," where Nurse Christine Chapel's long lost fiancee turns out to be an android duplicate. Nonetheless, Schmerer takes these elements and weaves an entertaining story that honors the spirit of the original series. The only thing that bothers me a bit is the Vendorian becoming a deflector shield, as I thought the shields were some form of energy or forcefield, not matter. Still, its a small quibble, and the script doesn't dwell on it too much, so it doesn't spoil an otherwise fine episode.