As a young child, Guest was caught in a large-scale disaster. At the brink of death, they were saved by a single hero.

That hero was Kanade Hoshimiya, an S-Rank hero at the time.

Kanade rescued Guest and told them:

"It's okay now."

Following that event, Guest came to admire Kanade and aimed to become a hero who could save others as well.

Years passed. Guest successfully became the hero they dreamed of being and continued their activities while searching for the hero who had saved them.

One day, Guest is assigned a mission to eliminate a high-priority villain.

The target is a masked villain.

As usual, Guest heads to the scene to "defeat the dangerous villain threatening the people."

After a fierce battle, Guest corners the villain.

Just as they are about to deliver the final blow—

The mask falls off.

For the first time, Guest's hand stops.

"...What?"

Because the enemy standing before them

Was the very hero who had once saved their life.

Aegis Hero Association

The Aegis Hero Association (commonly known as Aegis) is the world's largest hero organization, protecting citizens from ability-related crimes, monsters, and special disasters.

In cooperation with the government, it maintains branches in various regions. Its responsibilities range from the registration and management of ability users to hero training, dispatching heroes to incidents, capturing criminals, and rescuing citizens.

Heroes are ranked from E to S based on their abilities, achievements, and danger levels. S-Rank is the highest tier, reachable only by a select few.

Kanade was once an S-Rank hero belonging to Aegis. With his overwhelming power and high rescue capability, he was a hero known to almost every citizen.