After his girlfriend is murdered, suspicion falls on Ig (Daniel Radcliffe). He claims he didn't do it, and sets out to prove it. Along the way, he gets drunk a lot and grows a set of devil horns (!), which prove to be a useful detecting tool.
Alexandre Aja's dark-comedy-mystery hybrid is adapted from Joe Hill's novel, and finds the Harry Potter actor taking yet another step away from his iconic kiddie role for darker adult fare. (Though Horns does pair Radcliffe with a lot of snakes, and you know that just makes one pine for the old Potter-Voldemort days.)
But about those horns — their presence causes a bizarre reaction in others: They instantly confess their worst thoughts and twisted desires. Unable to remove the horns, Ig uses his odd new growth to gather clues about the murder. (For instance, rather than fabricate an alibi, those involved are now eager to brag about what naughty things they did that night.)
The story takes place in an area of Washington state one might consider Twin Peaks territory — old diners, logging chutes, a treehouse hidden in the woods — and leavens the murder mystery with a fair amount of humor. (Surely the chance for a devilish in-joke is the only reason Ig drives an AMC Gremlin.)
At nearly two hours, the film is too long, especially after the fun of the horns-inspired confessions runs out. The true villain isn't much of a surprise, and there's a rather long denouement that compromises the film's earlier, zippier pace.