僕の初恋をキミに捧ぐ (Series) favorite_border

[DeepL Translation - needs review] Introduction to Volume 1: Takuma, who is hospitalized for heart disease, and Mayu, the daughter of Takuma's doctor, are very close and always play together in Takuma's hospital room. One day, Mayu overhears his parents telling him that he will not live to be 20 years old. Mayu learns of Tatsuyuki's fate and somehow tries to cure Tatsuyuki's illness. Then, unaware of his fate, Rugaru asks Mayu, "Will you marry me when you grow up?" but...!

(Translator: DeepL)