This story takes place on a small farm with the narrator and his newborn little brother who was originally named William Armstrong but later named Doodle to better fit his personality.
The narrator had always wanted a little brother but is very disappointed when he finds out his brother has disabilities. He is not able to accept that his brother is different than most people.
The narrator is embarrassed that his brother is not like the other kids so he decides he will teach him to walk. After Doodle can walk, he wants to teach him to swim, run, and other things that the other kids can do. One day, the family sees a Scarlet Ibis that dies. None of the family seems to care besides Doodle.
One day when the narrator and Doodle were training, Doodle becomes too weak to continue. The narrator becomes irritated and they begin to go home. The narrator purposely begins to run faster than Doodle is able to. Doodle cannot keep up and is left behind.
When the narrator can no longer see Doodle, he goes back to find him. When he finds him, Doodle is laying dead with his neck in an 'S' shape, similar to how the Scarlet Ibis was laying.
The narrator then realized he was being selfish and was only doing this to Doodle because he was embarrassed of him. The narrator realized his selfishness had caused his brother to die.