 Lt. Cmdr. Data, on a mission to observe the race of Ba ku, suddenly behaves as if having to fear for his existance. The peaceful Ba ku, whose planet offers regenerative radiation and therefore incredible lifespans, live in harmony with nature and reject any kind of technology. Their planet and their culture is studied by the starfleet and the associated Son a - in secrecy. But the So na, lead by Ru afo, intend to abduct the Ba ku in order to take the planet for themselves and for the starfleet officials who all would like to regenerate their bodies. But they did not think of the loyalty of the Enterprise s crew to the Prime Directive.