S2·E27 The Phantom Family

Will returns to camp following a cosmic storm. John and Maureen are not there as they are at the weather relay station for a few nights. When he gets there, the rest of the family are acting strange. He finds out they are androids, sent to learn how to cope like the Robinsons and teach the rest of their race when they return home. The real Robinsons, are kept in a tube, as they are not allowed to come in to contact with thier double. Will must teach them to become like their counterparts.