"The Deadly Years" is the twelfth episode of the second season of the American science fiction television series Star Trek. Written by David P. Harmon and directed by Joseph Pevney, it was first broadcast December 8, 1967. In the episode, strange radiation causes members of the crew of the Enterprise to age rapidly. Plot The USS Enterprise is ferrying a senior officer, Commodore Stocker, to Starbase 10 where he is due to assume command. On the way, the ship makes a stop at planet Gamma Hydra IV to resupply the research station there. A landing party consisting of Captain Kirk, First Officer Spock, Chief Medical Officer Dr. McCoy, Chief Engineer Scott, navigator Ensign Chekov, and Lieutenant Arlene Galway beam down to the facility. The station seems completely deserted, until Ensign Chekov discovers the body of a man who apparently has died of old age, and panics. Robert Johnson, a member of the station crew, appears with his wife Elaine. Both claim to be in their late 20s, yet appear 50 years older. The two soon die in the Enterprise sickbay. Mr. Spock and civilian scientist Dr. Janet Wallace begin an investigation. Their only clue is a comet that passed Gamma Hydra IV recently. Soon the landing party, with the exception of Chekov, begin to age rapidly as well. Lt. Galway ages most rapidly and soon dies. By now they have learned that the comet gave off low-level radiation that most likely caused the aging effect. As Kirk continues to age, he becomes increasingly forgetful, including ordering the use of an obsolete code despite having recently been told the code had been broken by the Romulans. This leads Commodore Stocker to order Spock to convene a hearing, in which Kirk is found unfit to command. With Spock also afflicted, Stocker assumes command, and orders a direct course to Starbase 10, ignoring warnings that this will take the ship through the Romulan neutral zone. Meanwhile, Kirk, McCoy, and Spock discuss Chekov's immunity to the affliction. Remembering Chekov's fright at the discovery of the dead body, McCoy surmises that Chekov's increased adrenaline levels may have had some effect, and recalls that adrenaline had once shown promise as a treatment for radiation sickness. Mr. Spock and Dr. Wallace, assisted by Nurse Chapel, begin work on an adrenaline-based compound to test on the landing party. As Enterprise enters the neutral zone, Romulan vessels attack, ignoring