Ten-year-old Aurora has a mysterious neighbor (Mads Mikkelsen) who kills real-life monsters. He's a hit man for hire. So, when Aurora needs help killing the monster she believes ate her entire family, she procures his services. Suspecting that her parents may have fallen victim to assassins gunning for him, Aurora's neighbor guiltily takes the job. Now, to protect her, he'll need to battle an onslaught of assassins -- and accept that some monsters are real.