- For other uses, see Miri.
Miri was born on the Earth-like planet, Miri's homeworld, in that world's equivalent of the 1950s decade. Due to a life-prolongation experiment being conducted on the planet around the time of her birth, all the children on the planet had greatly increased life-spans, while all of the adults perished.
When the USS Enterprise arrived in orbit in 2266, Miri was over 300 years old. When the landing party encountered Miri she was very frightened of the "Grups", but later developed a liking to the humans and an attraction to Captain James T. Kirk. Because of Miri's position of respect for caring for the younger Onlies on the planet, she was able to convince the children to trust the Enterprise landing party and allow them to develop a cure for the life-prolongation drugs that were killing them. (TOS episode: "Miri")
When the Enterprise left the planet, they left behind a team of experts to educate the Onlies and help them to assimilate to a new way of life, with Miri's support and guidance. Jahn, however, repeatedly rebelled against their authority and eventually, together with a younger girl named Rhea, managed to sneak onto a Federation supply vessel, the USS Sparrow and take control of the ship, with which he planned to leave the planet. When he tried to persuade more Onlies to join him in leaving, a firefight with Federation personnel ensued, in which Miri was killed by a stray shot. Her death led to one of her oldest friends, Jahn, seeking to avenge her death against the Federation. (TOS novel: The Cry of the Onlies)
When the infection began to reassert itself among the Onlies, many of whom were then teenagers and young adults, they became frustrated and rebelled against the grown-up authorities sent to watch over them. Jahn sought revenge by stealing a shuttlecraft and attempting to kill Joanna McCoy, as retribution for Miri's death. Admiral Kirk, McCoy and Joanna were able to defuse the situation. Kirk paid a solemn visit to Miri's grave. (TOS - Untold Voyages comic: "Past Imperfect")
Because of her young age (and their friendship being out of desperation and necessity to get her peers to "clique" with the adults), Miri may not fall under the Kirk's women category. However, as she matured in the episode she felt attracted to James T. Kirk, her mentor, and a 1995 TV Guide issue featured actress Kim Darby as one of the many female acquaintances known to William Shatner's Star Trek role.