One day, while returning home from a karate tournament in Hokkaidō, he is involved in a tragic school bus accident and burned beyond recognition.

One year later, Masashi awakes from a coma to find that he has been in the care of a talented (yet slightly deranged) surgeon named Jun Manabe.

Afterwards, Masashi finds out that during his year long coma, he was mistakenly pronounced deceased, his parents moved away, and even his house was demolished.

On his way back to Manabe's clinic, he runs into Rina by chance, and is mistaken for her missing twin sister, Yuna.

After Rina takes him back to her house and presents him as Yuna, he lies about having amnesia in order not to arouse any sudden suspicions.