Sachiko, the seventeen-year-old daughter of Professor Shigeru Ōshima, a deputy professor at the Faculty of Medicine at Tōto University, was a beautiful and kind-hearted girl. However, fate subjected her to an early and cruel trial. In a research accident, she was exposed to radiation and diagnosed with leukemia. Her life became intertwined with hospitals, blood transfusions, and treatments. Alongside her fate was Mitsuo Sagara, a medical student who developed deep feelings for her after repeatedly donating blood to sustain her life.

Yet destiny showed no mercy to their love. The devastating truth emerged—Sachiko was not Shigeru Ōshima’s biological daughter but rather Mitsuo’s half-sister, sharing the same father. This revelation plunged them into deep anguish and despair. Even more cruelly, Sachiko had only six months to a year left to live, dooming their love to an inevitable end.

Despite this, Mitsuo remained by her side, steadfast in his devotion. Wanting Sachiko to experience happiness in her remaining days, Ōshima allowed Mitsuo to stay with her. Meanwhile, Mitsuo’s father, Eiji Sagara, harbored professional resentment toward Ōshima and even attempted to have him removed from the Department of Nuclear Medicine. However, Ōshima paid little mind to these conflicts, knowing that the only thing that truly mattered was continuing Sachiko’s treatment.

Torn apart by the truth of their relationship, Mitsuo tried to distance himself, hoping to forget the love that could never be. Yet, at Ōshima’s urging, he ultimately returned to Sachiko’s side. Though they could not change their fate, their time together was filled with warmth and mutual dependence.

To fulfill one of Sachiko’s wishes, Ōshima decided to take her to Paris to reunite with her biological mother, Rie. There, her illness struck again. Though Rie was devastated upon learning of Sachiko’s condition, she hid her sorrow and continued to smile by her side, offering a mother’s gentle love as a shield over her fragile heart.

However, her condition continued to worsen. On the return flight from Paris, Sachiko suffered another severe episode, barely surviving after emergency treatment. Hearing of a rumored gypsy herbal remedy for leukemia, Rie sent the medicine along with a letter. But in reading the letter, Sachiko discovered the full truth about her illness, plunging into deep despair. Fortunately, Rie’s reassuring words comforted her, and she gradually regained her composure.

Even in the face of death, Sachiko clung to her love for life. She and Mitsuo welcomed a New Year together in a breathtaking snowy landscape. When their car broke down along the way, they displayed remarkable resilience, embracing each moment. She dreamed of applying to medical school, hoping to contribute to the world with her efforts. Yet fate struck again. Mitsuo received an offer to study in the United States, and the distance seemed to push their love even further beyond reach.

Though the news shook Sachiko, Mitsuo’s reassurance calmed her. However, in an unexpected turn of events, she discovered her true parentage—she was, in fact, related by blood to Mitsuo’s father, Eiji Sagara. The revelation overwhelmed her, and she chose to escape to Hokkaido, seeking solitude from the unbearable pain. Yet both Mitsuo and Ōshima pursued her, eventually finding her in Sapporo and encouraging her to confront life once more.

As her condition deteriorated, Sachiko gradually lost her vision, and the disease infiltrated her brain. In a desperate attempt to save her, Mitsuo carried out a bone marrow transplant, briefly extending her life.However, Sachiko knew her time was running out. With calm acceptance, she bid farewell to her loved ones, leaving behind cherished memories. In Mitsuo’s embrace, she passed away peacefully.

Her death left an indelible mark on those she touched. Inspired by her resilience, Ōshima spoke of her courage to medical students, urging them to face life’s hardships with bravery. As for Mitsuo, he resolved to study in the United States, dedicating his life to finding a cure for leukemia and helping those who suffered as Sachiko did.

Though short-lived, Sachiko and Mitsuo’s love became an eternal symbol—two hearts brought together by illness, yet torn apart by fate. And yet, their love, filled with warmth, strength, and beauty, remains one of the most touching legends of all time.