The day that Ig sprouts his horns is a long and disturbing one for the mourning, self-destructing Perrish. He can't quite remember what he did when he got drunk the night before. When he stumbles out of the bedroom, his new girlfriend tells him she wants to do something so disgusting he will leave her—then asks permission to eat an entire box of expired doughnuts. The two cops that pull Ig over later that day admit that they think he killed his former girlfriend, Merrin Williams, and that they're waiting for him to make a mistake. Ig's doctor offers him Oxycontin before the young man heads to his parents house, thinking that at least they will believe that he didn't kill Merrin. No such luck, unfortunately. But Ig's brother, Terry, lets a secret slip that puts Ig on the trail of the man who really killed Merrin—Ig's lifelong friend, Lee Tourneau.
All this happens in the first blistering chapters of Horns. I can only describe Horns as a blend of magic realism and horror. After a day, Ig settles into his horns and newly found diabolical abilities remarkably well. No one else remembers the horns after a bit, let alone that they asked Ig if they could indulge in their dark little sins and yell at a screaming toddler or tell Ig that they wish he would kill himself. Curiously, only Lee Tourneau seems immune to Ig's abilities. There's something not right about him, too, which Hill takes his time revealing to us. Even though Ig is sporting devil's horns, it's clear that Lee is much more terrifying and dangerous than Ig. This book shares an acceptance of the supernatural that I've only seen in magic realism. Lee's evil and Ig's horns just are.
After Terry tells Ig what he remembers of the night Merrin was killed, Ig decides that he must avenge her by murdering Lee. This is easier said than done, because Lee is uninhibited when it comes to violence. Ig just doesn't have it in him. Things get even stranger after Lee sets Ig's car on fire, locks him inside, and tries to drown the would-be avenger.
Through flashbacks and the glimpses of the past Ig gets when he touches someone, we learn how Lee killed Merrin and why. Lee is a sociopath who has managed to escape detection so long because he models his behavior on Ig's. Ig is a wreck when we meet him at the beginning of Horns, but he was a truly good person. He was a believer about to take a job with Amnesty International, for crying out loud. But Lee, well, Lee is always out for himself. And he's always wanted Merrin. Because he is incapable of believing that Ig and Merrin don't have ulterior motives, Lee misinterprets everything they say and do—all of it leading to the terrible night Merrin dies.
Horns is a chilling book. Without the horror and magic realism elements, I could see this story playing out anywhere. With them, the story becomes an incredible meditation on good and evil, revenge, and love.