Ensign C. Plummer was a male Human Starfleet sciences division officer who served aboard the USS Enterprise under Captain Christopher Pike in 2254.
That year, Plummer was officially reported as being among the casualties during an incident with the Kalars on Rigel VII, specifically one of the three who were reported killed during the mission. (TOS: "The Cage")
Five years later, his personnel file image appeared during the briefing on the Enterprise's return to the planet. (SNW: "Among the Lotus Eaters")
Plummer was depicted in a photo by an unknown actor.
He may be named after veteran Star Trek actor Christopher Plummer.