The station is beginning to run out of resources, and therefore sends a group of teenagers down as a vanguard to begin the process of recolonizing the Earth.
- The teenagers sent are those that broke the law
- One of the convicts is a boy falsely accused of getting a higher caste girl pregnant
- There are castes, and each has its own section on the space station
- The aforementioned girl and some guy (either her actual lover or the prisoner, my memory is hazy), go around the ship as oxygen begins to run out
- They're caught on opposite sides of a barrier designed to save the higher caste section, they go into some sort of vent though and suffocate
- As far as I'm aware, the convicted kids escape and make it to Earth's surface