Starting around 2246, Adams began the work that would revolutionize prisons and the treatment of prisoners. His theories transformed prisons from cages into clean, decent hospitals for sick minds. Captain James T. Kirk believed Adams' work had done more than the rest of Humanity had done in the previous forty centuries. This auspicious beginning made Adams' tenure at the Tantalus Penal Colony and subsequent death baffling to those who knew him.
In early 2266, Dr. Simon Van Gelder joined Dr. Adams as an associate. Six months later, Van Gelder was severely ill, barely able to remember his own name. When the USS Enterprise visited the colony for routine resupply, Van Gelder managed to escape. Dr. McCoy did not believe Dr. Adams' explanation for Van Gelder's illness. Regulations required Kirk to investigate; he visited the colony, along with Dr. Helen Noel, to meet with Adams and learn what had happened to Van Gelder.
Spock and McCoy eventually learned that Van Gelder had been injured by Adams himself, who was conducting unauthorized and unethical experiments on all the patients and staff-turning them-with the exception of Van Gelder-into mindless Zombies. By the time they learned this, Adams had imprisoned Kirk and Noel, and was subjecting Kirk to the neural neutralizer, with the declared goal of learning more about this form of therapy.
Noel, acting on Kirk's instructions, managed to briefly shut off the power to the facility as part of an escape attempt. During the scuffle that followed, Adams was left stunned on the floor of the neural neutralizer treatment room, and Kirk escaped. When Spock restored power a few moments later, he also unwittingly restored power to the neural neutralizer, Adams was still in the room, and was subjected to unsupervised exposure to the beam for an extended period. This exposure emptied his mind, killing him. (TOS: "Dagger of the Mind")