In a world where all plant life is gone, Freeman Lowell (Bruce Dern) is in charge of a huge greenhouse in space. Lowell is ordered to jettison the domes containing the forests, but he decides to try and save them instead. He has a fight with a crew mate who is trying to destroy the forest and ends up killing him. Two remaining crew members are trapped in another dome and Lowell destroys it killing the crew members. The ship has three service robots that Lowell teaches to plant trees and take care of the greenhouse. Lowell soon realizes that the forest he fought so hard to save is dying and he must try to figure out the reason. He finally figures out what is killing the forest and comes up with a plan to try and save it.