She assumed both positions during Pavel Chekov's absence when a landing party to Gamma II on stardate 3211 went missing, captured by the Providers of Triskelion. (TOS: "The Gamesters of Triskelion"). While the Enterprise crew was looking for any phenomenon that could help explain how and why the landing party went missing, Haines (working at the science station on the bridge) noticed and reported a barely detectable but consistent fluctuating energy reading in a distant hydrogen cloud. The Enterprise computers were able to identify the reading as an ionization trail, and Spock, acting as ship's captain in the absence of James T. Kirk, theorized that the trail might lead to the missing landing party. The Enterprise was able to follow the trail to Triskelion, with Haines acting as navigator.
Haines was played by Victoria George. Unlike most other ensigns, who are normally portrayed as recent Starfleet Academy graduates in their early 20s, this character appears to be in her late 30s or early 40s. The character's full name and rank ("Ensign Jana Haines") appears in the credits, but the first name Jana is not spoken aloud in the actual episode.