It is 640 days after leaving Earth orbit, and Alan Carter sings an absurd ditty as he strides through an underground mining gallery beneath . Mineralogist Andy Johnson leads the way, searching for dylenide crystals (a component in the Eagles' atmosphere-scrubbing filters). The two mates banter as they set up a sonarscope and begin probing the cavern walls for the mineral. Johnson soon detects a mineral formation that is definitely "not" dylenide. Using the 'scope's thermal cutter, they uncover a transparent cabinet—containing two persons.