Arleen was a female Human who was a member and staunch supporter of the Anti-Federation League in the 23rd century. In 2267, Arleen and five other members acquired the Marquis-class yacht, SS Harmony, on a mission across the Klingon Neutral Zone to establish diplomatic and peaceful with the Klingon Empire.
Shortly after crossing into Klingon territory, the unnarmed Harmony was attacked by the IKS B'Ardaq, a cargo vessel. The Harmony was soon overwhelmed and Arleen and the other Humans were taken prisoner. While being held captive aboard the B'Ardaq.
Eventually, Arleen and three others were rescued alive by Lieutenant Michael Fuller and a security team from the USS Enterprise, and were treated by the Enterprise's medical staff. (TOS novel: Demands of Honor).
- No surname was given for Arleen.