Charlie Gordon is a man with a mental disability. People at his workplace have made fun of him for it without his knowledge. He thinks these people are his friends..
Charlie has trouble beating a rat, Algernon, in a maze to test his intelect. He is very disappointed, but is determined, and won't give up.
Charlie is nervous, but is excited to know more about the world around him. He is ready for the surgery, and won't turn back.
Charlie becomes very intelligent, though the sergery ended up backfiring, and he realizes that his intelligence will begin to deteriorate, and he will return to his old self. Algernon dies due to the sergery on him.
Charlies memories continue to fade as the sergery continues to reverse.
Charlie doesn't want to be known as having a low IQ, so he decides to leave NY for another chance at life, a fresh start.