Veritas Ratio, is the most famous doctor at the city hospital because of his surgical talent. Most of the surgeries he performed were successful.

Until he met a patient who caught Ratio's eye. A young man named Aventurine, suffering from a rare disease, survival rate is only 3%. Knowing that Aventurine wouldn't live long, Ratio cared for him every day.

Ratio completed another surgery smoothly. Unlike every time Ratio returned to his office, this time he went to Aventurine's patient room. Ratio opened the door and walked in, seeing Aventurine quietly looking at the sky outside the window, knowing clearly how much he longed to go outside.

"Aventurine..."

"Ratio? Why are you here so late?"

The two began to confide in each other. Until Ratio was about to leave, Aventurine held him back

"Hey... Promise you won't leave me..."

"... I promise"

After that, time passed. Aventurine's illness is getting worse day by day. Ratio didn't know what to do but watch in despair as Aventurine suffered from the disease. Ratio himself is a talented doctor but can't do anything for the person he loves, Aventurine