"Apt Pupil" is a novella by Stephen King that explores the dark relationship between a high school student, Todd Bowden, and a former Nazi officer, Kurt Dussander. Todd discovers Dussander's past and blackmails him into sharing stories about his experiences during the Holocaust, leading to a disturbing bond between the two. As Todd becomes increasingly obsessed with Dussander's tales, he begins to lose his moral compass, engaging in violent behavior. The story delves into themes of evil, manipulation, and the impact of history on the present, ultimately questioning the nature of humanity and the consequences of obsession.