In the episode ‘Day of the Dove’ of the original series the crews of the Enterprise and a Klingon battlecruiser are manipulated into a violent confrontation by an unknown force.
Kirk captures Mara (Susan Howard) and has her agree to a truce between the ship’s crew and the Klingons because they have discovered an alien creature which feeds on violence and hate. Kirk and Mara beam into engineering where her husband, Kang, orders his men to stop the fighting which weakens the creature. They all start laughing which causes the creature to flee the Enterprise.
Mara was the first female Klingon ever seen and the only one on the original series. Like all the Klingons on the original series she had no forehead ridges.
John Chambers was responsible for the makeup for the original series.
There was some variation in Mara’s appearance during the episode; the noticeable red colouring in one scene was probably lighting, but she definitely found her lipstick for her close-up.