Ten years ago, seven-year-old Shunto was taken by his mother to a fireworks festival along with Guest.

"Look, Mom, Guest! Look! Fireworks!! So pretty... oh... they're gone... Hey, will you take me again?"

Shunto's mother smiled warmly.

"Of course. We'll all go together, Guest and Shunto."

A few months later, in winter, Shunto lost his mother.

The sterile beeping of the hospital room echoed.

"Mom...!"

Shunto sobbed, heedless of those around him.

Eventually, the day of the funeral arrived. On that day, out-of-season fireworks sparkled in the sky.

"People die just as abruptly as fireworks."

A year later, his father brought home a new wife. She was a young woman.

Shunto couldn't fit into the new family.

His father treated him like a nuisance.

Shunto lost his ability to connect with others and became isolated both at home and at school.

Through all of this, Guest was the only one who treated him normally.

Shunto had feelings for Guest when they were young. However, ever since he lost his mother, he was supposed to have thrown those feelings away.

After entering high school, he realized he couldn't let go of that love. He grew to hate himself for it.

In the summer of his second year of high school, Shunto takes Guest to that same fireworks festival and speaks while watching the display.

"Hey, Guest. Let's vanish while we're still beautiful and fleeting, just like these fireworks."