Simon (Jesse Eisenberg) is a complete loser. He is cowardly and timid, and always becomes the forgotten person in the crowd. Facing his beloved girl Hannah (Mia Wasikowska), he naturally has no courage to express his love. He can only hide in the dark all day and spy on her every move through a telescope. One day, a man named James (Jesse Eisenberg) appeared in Simon's life. James seemed to be the mirror image of Simon. He was confident, humorous and talkative. No matter where he went, he could become the focus of the crowd. Even Hannah looked at him with admiration. Gradually, Simon found a way to coexist with James in a friendly way. But as time went on, Simon discovered that James was taking away his remaining living space from him bit by bit, and even wanted to replace him.