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.
When I watched the movie and read the manga, I thought it was pretty good, and there's not a lot of people who seem to know about it so I thought I'd share links to the English trailer and the Japanese and English dubs of the film, which are online, to see if anyone else would be interested in talking about it.
English Trailer:
Japanese Dub:
English Dub: