They Were Eleven (11人いる! Juichinin Iru!) is a manga by Moto Hagio which ran in Shoujo Comic for three issues from September through November 1975. It was awarded the Shogakukan Manga Award for shōnen in 1976.

The manga was adapted as a one-episode, 40-minute television drama broadcast on 1977-01-02 as part of the Shounen Drama Series on NHK. Ten years later, it was adapted as a theatrical anime movie, released November 1986. In 2004, a theatrical stage adaptation was produced.

Ten young space cadets are put onto a decommissioned spaceship as their final test. If they pass this test, their lifelong dreams of being valued people in their respective societies will come true. Their orders are to survive as long as they can with what they have. However, once they arrive at the decommissioned ship, they find that their crew has gained an eleventh member. As the days pass, the eleven cadets must deal with their suspicions of each other as well as the sudden knowledge that the spaceship is in a decaying orbit around a star, which is causing the temperature on the ship to rise. With this rise in temperature, a sickness begins to spread among the crew as they work to stabilize their orbit and determine who among them is the spy.

- From Wikipedia