When Roland Doyle wakes up in an unfamiliar motel room with a strange man’s wallet in his pocket and a woman’s dead body in the bathroom, he fears the worst…and that’s before he finds the vial of pills labeled "take one every 4 hrs or else." Or else what? Ten years ago, Dr. Sebastian Briggs’s clinical drug trial for a cutting-edge fear-response drug went horribly wrong — or did it? It’s true that one trial participant died and five others were left with no memory of what happened to them. But now several interested parties, including a major pharmaceutical company and an ambitious U.S. senator, are willing to back Briggs’s continued research. All he has to do is recall his five surviving "volunteers," whose addiction to a mysterious drug has left them largely at his disposal. They will do anything necessary to keep the pills coming and to stave off the creeping phobias, intense sexual impulses, and all-consuming madness that lurk on the edges of their minds. It’s easy enough for the good doctor to lure the survivors back to the remote Monkey House, where the original trials took place. But when the pills finally run out…that’s when the real show begins.