On the "Enterprise" van Gelder becomes increasingly frantic, warning that the landing party is in danger, but when he tries to explain the danger and refers to the neural neutralizer, he is convulsed with pain. Spock mind-melds with van Gelder to enable him to tell his story. Spock learns that the neural neutralizer can empty a mind of thoughts, leaving only an unbearable feeling of loneliness, and that Adams has been using it on inmates and staff to gain total control of their minds. The first officer assembles a security team, but the colony's force field blocks transport and communication.