Offspring takes place on the Cradle, an alien world of technical mastery, homeworld of the radji people. Their planet is a fortress, their sole enemy, the violent and predatory pyq, are kept far at bay. Little do any know that one day their fortress will come tumbling down. A radji couple, ecologists and pariahs of their own people, find a strange egg, and are shocked when it hatches a pyq. Faced with imprisonment should the child be discovered, the pair are left with an impossible choice.