Akari Hizamaru is one of a hundred crew aboard the Annex I, the third human mission to a Mars overrun by Terraformars, towering humanoid roaches descended from cockroaches seeded by an earlier terraforming attempt. The crew carry the Mosaic Organ, a procedure that splices an Earth creature's traits into a human body; Akari's gives him the near-invisible silk of the bagworm moth. Their orders are to capture live specimens and bring home a cure for the A.E. virus killing Earth's population.