They Were 11 is about ten Galactic University recruits who have passed many levels only to be given one final test. They are told to travel to an ancient spaceship and live there, together, for fifty-three days. This is not a problem until the ten recruits, hailing from diverse backgrounds and planets, discover that there are actually eleven of them on the ship. In fact, this problem turns out to be the test, as they have to trust each other in order to survive, even though one of them is an impostor.
 
(Source: Viz Media)
 
Note: Won the 21st Shogakukan Manga Award for Shoujo in 1975.

In the distant future, ten space cadets embark on a survival test that sets them adrift in a derelict spacecraft from which they must find their way home. Terror strikes when the cadets discover eleven of themselves aboard the ship. Who is the imposter, and what is his (or her) purpose? Paranoia runs rampant and lives hang in the balance as the cadets scrutinize one another for any wrong move. Can they identify the spy before it’s too late? 
 
(Source: Central Park Media)

Chako Kacka