Naoto Sasaki is beginning his first year at medical school when he encounters a vibrant girl named Miu Minehara in a park filled with cherry blossom petals. She is bold and direct, immediately declaring herself his girlfriend and dragging him on a boat ride. What Miu does not know is that Naoto carries a heavy secret: through a simple touch of the hand, he can see the exact number of days a person has left to live. As a child, he witnessed this countdown above his dying mother's head, and now, after taking Miu's hand, he sees the number 300 hovering above her. Despite this crushing knowledge, Naoto accepts her impulsive proposal. His shock deepens when he arrives at medical school on the first day of class only to discover that Miu is a fellow student. As their spontaneous encounter transforms into a real and serious romance, Naoto must grapple with the unbearable awareness of their ticking clock. Miu, unaware of her fate, decides to live every moment to its fullest, pushing the timid Naoto to come out of his shell and experience life. Together, they strive to create a normal, happy relationship even as the dreaded day of farewell approaches, forcing them to confront the painful reality of her incurable illness and impending death. The story is a two-volume tragic romance drawn by Kohei Nagashii, emphasizing the beauty of fleeting springtime moments against the inevitability of loss.