"The Man Trap" is the first episode of season one of the American science fiction television series Star Trek. Written by George Clayton Johnson and directed by Marc Daniels, it featured design work by Wah Chang and first aired in the United States on September 8, 1966. In the episode, the crew visit an outpost on planet M-113 to conduct routine medical exams on the residents, only to be attacked by a shapeshifting alien who kills by extracting salt from the victim's body. This was the first Star Trek episode to air on television, although the sixth to be filmed; it was chosen as the first of the series to be broadcast by the studio due to the horror plot. "The Man Trap" placed first in the timeslot with a Nielsen rating of 25.2 for the first half-hour and 24.2 for the remainder. It aired two days earlier on Canadian network CTV. Plot The USS Enterprise arrives at planet M-113 to provide supplies and medical exams for the only known inhabitants of the planet, Professor Robert Crater (Alfred Ryder) and his wife Nancy (Jeanne Bal), who operate an archaeological research station there. Captain Kirk, Chief Medical Officer Dr. Leonard McCoy, and Crewman Darnell (Michael Zaslow) transport to the surface as Kirk teases McCoy about his affection for Nancy ten years earlier. They arrive in the research station, and each of the three men sees Nancy differently: McCoy as she was when he first met her, Kirk as she should look accounting for her age, and Darnell as an attractive blonde woman whom he met on a pleasure planet. When Nancy goes out to fetch her husband, she beckons Darnell to follow her. Professor Crater is reluctant to be examined, telling Kirk that they only require salt tablets. Before McCoy can complete the examination, they hear a scream from outside. They find Darnell dead, with red ring-like mottling on his face, a plant root in his mouth, and Nancy standing over him saying she was unable to stop Darnell from tasting the plant. On board Enterprise, Spock analyzes the plant. He confirms that it is poisonous, but that mottling is not a symptom. McCoy conducts a medical exam and, together with Spock, determines that all the salt was drained from Darnell's body. In response, Kirk transports back down to the planet with McCoy and two crewmen, Green (Bruce Watson) and Sturgeon