Their mission is simple.  Get home.

On an ambulance ship filled with critical patients, the medical students of Caelum Station are only concerned with getting their patients back to the teaching hospital and being selected to observe from inside the surgical suites.

When their starship crashes out of warp because of a subspace Blackout, their options are limited.  Without understanding the scale, range or origins of this phenomenon, they set out in shuttles to find a raggedy edge of the Blackout, so they can warp back to Caelum Station.

With only impulse engines to carry them, distance is the true enemy.