In the animated short "Birthday," the story follows a character who eagerly prepares for their special day. As they set up for the celebration, they encounter various challenges, such as inviting friends, decorating, and baking a cake. 

Despite the initial excitement, the character faces moments of disappointment and uncertainty, especially when friends seem to be busy or when things don't go as planned. However, the story takes a heartwarming turn when loved ones surprise the character, showing that the true essence of a birthday lies in the connections we have with others. 

Ultimately, the short emphasizes themes of friendship, love, and the joy of shared moments, reminding viewers that the people in our lives make celebrations truly special.