Love until death do us apart, but the time is ticking towards its limit. Takuma has a heart disease and the doctor tells him he won’t be able to live up to 20 years old. He and the doctor’s daughter Mayu are friends from their childhood. When they were children, Takuma asked her to marry him and Mayu answered, “Promise to marry me when we become twenty!” Takuma had never questioned his future with Mayu until he found out that he won’t be able to live long. Ever since Mayu found about Takumi’s life expectancy when she was still a child, she has devoted her life to find out a way to save Takuma. The one and only wish of Takuma and Mayu is that they can live their lives with the person they truly love, that is together. This is a story of two high school students bound by love but facing the time limit of life; a heart aching but beautiful love story where a young couple struggles to fight against their destiny to make their dream come true.