When Dr. Wesley Legion's twin sister, Rachel, dead for twenty-six years, speaks to him, he dismisses it as a trick of his imagination. But when it occurs again, this time feeling her presence and the touch of her hand, he cannot but relate it to the symptoms of one of his patients for whom he has ordered Electro Convulsive Therapy. Now, doubts about his professional judgment and the very tenets of psychiatry threaten to destroy his career as well as his carefully constructed persona. At home in upscale La Jolla, his beautiful wife, Ashley, their six-year-old son, Davie, and his devoted Aunt Winnie, complete a picture of harmony. But it's an illusion, shattered by his wife's abuse of alcohol and his remoteness. With the onset of hallucinatory symptoms, doubts about his profession and marital discord collide, he escapes to the Mojave Desert determined to locate the cave in which Rachel died and solve the puzzle of her death. The desert offers a rugged terrain of mystery and serenity, of danger and romance. It's here that he meets Ginger and Samantha, learns the myth of the caves, and encounters phenomena that will forever challenge his belief system.