Tatsuya was born as the second son of three brothers. His mother, Yumi, had the impression that he was a quiet child who didn't assert himself... But one spring, his older brother got a job and lived alone, while his younger brother entered a boarding school on a sports recommendation. Their father moved away from his family for work, and their lives changed drastically, leaving them to live alone with their mother. The lively house suddenly became quiet, and Yumi felt a sense of loss. Seeing his mother like that, Tatsuya felt an indescribable jealousy, and tried to regain the love of his mother that he had never had the chance to monopolize...