Matt Reeves had a very difficult task writing and directing Let Me In because his adaptation quickly follows on the heels of director Tomas Alfredson's brilliant film Let The Right One In whose screenplay was written by the book's author John Ajvide Lindqvist. Although people with remake aversion were right to be nervous when first hearing about Reeves' film due to Hollywood's recent track record, he honors the source material by creating a very good film that plays up the horror elements.
Transporting the story from Sweden to the United States, Let Me In opens in 1983 at a New Mexican hospital with an officer identified as The Policeman (Elias Koteas) attempting to interview a severely injured man who doesn’t respond. The Policeman is called away to the phone, and while out of the room, the patient falls out a window to his death from ten stories up.
The story then jumps back two weeks where we meet Owen (Kodi Smit-McPhee), a twelve-year-old boy struggling with his parents' separation, which leads his mom to drinking, and bullies at school picking on him relentlessly. Into his apartment complex Owen sees Abby (Chloe Moretz), a girl about his age, and her father (Richard Jenkins) move in. One evening Abby approaches Owen and tells them they can't be friends, yet she keeps coming out to the apartment complex courtyard to chat with him. Eventually, she is proven wrong as a bond forms between the two. They exchange puzzles and tap Morse code messages through their shared bedroom wall.
Although Owen sees the windows covered up, the audience learns before he does that Abby is a vampire. Her father goes out and kills a young man but fails to bring home blood. Starving, Abby goes out on her own, leaving behind a mess her father has to clean up. When Owen learns about Abby, he is understandably frightened, yet she reveals a vulnerability to him and regains his trust. They have an obvious affection towards each other but where can it lead? Especially when the police investigation in a string of recent, grisly murders leads to their apartment complex when one of Abby's victims is a neighbor.