What is the major conflict in the the key to midnight?

In "The Key to Midnight" by Dean Koontz, the major conflict revolves around the protagonist, John Keller, who is drawn into a web of mystery and danger as he investigates the disappearance of a woman named Melinda. Keller discovers that Melinda's past is intertwined with a sinister organization conducting mind control experiments. As he delves deeper, he faces not only external threats from the organization but also internal struggles related to his own traumatic past. The tension escalates as Keller races against time to uncover the truth and save Melinda from a fate worse than death.