Takano Tatsurou doesn't care much about life ever since his father abandoned him when he was little. Now he lives his life taking punches for money and working with the yakuza. His life changes completely when he gets to know he has an older half brother named Teru who is an autistic person and was also abandoned by his parents. Teru gets to move in with the seemingly coldhearted Tatsurou whose views on life start to change slowly. Things get complicated when Tatsurou finds his brother has a debt to pay back. The two brothers and their friend Tamaki have to go through many hardships to find their happiness.