Bartholomew was the leader of the Deltan people. For some unknown reason, his people had ceased to age beyond adolescence, and Bartholomew attempted to kidnap Penny and Will Robinson in order to use transfusions of their blood to give him and his companions the ability to grow up normally. His plan was foiled, but John Robinson tried to convince them that changing their hedonistic and self-centered lifestyle would allow them to grow up. Bartholomew seemed to consider that possibility for a brief moment before returning to dancing.