After being drawn into a meeting of Real Truth, Colin and Vanessa accidentally cross over into a parallel-universe Earth in which mental powers such as psychokinesis are practised by a number of adepts, who use these powers to enslave the rest of the population. It is explained that these abilities originated thousands of years past as the result of a mutation which the adepts carry. The leader, Telthis, is the one with the strongest mental powers, and has been using his abilities to influence events on Colin and Vanessa's Earth with the purpose of eventually invading it and ruling both Earths. It was Telthis's efforts which caused Colin's breakdown and hallucinations. Telthis also manipulated Colin and Vanessa into their apparently random meetings, because they also carry the genetic mutation of the adepts on Telthis' Earth, and he hopes that by bringing them together they will eventually have children and promote psychokinetic and other mental powers. Kolok, it turns out, is Telthis' chief opponent, who has appeared to Colin and Vanessa in the hope of preventing this.