The main character in this story is an introverted bookworm who isolates himself from the world around him. He believes that no one is interested in him, and he has no interest in anyone else. However, his life takes an unexpected turn when he discovers a secret diary titled "Living with Dying" written by his popular and lively classmate, Sakura Yamauchi. In the diary, Sakura reveals that she is suffering from pancreatic disease, and her time left is limited. Despite his initial lack of empathy, the protagonist is drawn in by Sakura's positive outlook on life and eventually agrees to accompany her on her journey. Through their interactions, the two individuals who are polar opposites develop a deep connection that influences their decision and shapes the way they live each day. As Sakura's carefree and unpredictable nature disrupts the protagonist's solitary existence, he learns to open his heart and embrace the true essence of living.