It is the year 2237. After the earth has become uninhabitable due to an ecological collapse, the remaining people live on overcrowded space stations in earth's orbit. The young doctor Laura Portmann is one of them. She hopes for a better future on the distant planet Rhea. But to get there she needs money. She signs up for a job on the derelict cargo ship Kassandra, heading for a 4 year flight to Station 42.