Imagine that all your life you've been guided by someone else. Someone who's steered you away from trouble, taken you across the world, brought you success. He's called Santiago and he lives in your head—and now he's turned against you. The unnamed narrator of this debut novel blunders through life, never quite getting things right until the arrival of Santiago, a male presence who appears in her mind at the age of 14. Thanks to him, the naive innocence that has led her into trouble so many times is gone, replaced by a street-smart wisdom that makes her attractive and successful, with a ruthless streak that gets her out of sticky situations time and time again. But as time goes by, Santiago's good advice becomes increasingly paranoid. From his operations room inside the narrator's mind he tortures her with old photos, maps, videos—the story of everything that has ever gone wrong in her life. He causes fits and hallucinations, anything to get his way. Suddenly Santiago is dangerous, and will stop at nothing to be in control.