Months of planning finally pay off when U.A. High announces an international cultural exchange program. Thanks to a partnership between the Japanese and American school systems, Class 1-A is sent on an all-expenses-paid educational trip to Alto, Georgia, a quiet rural town chosen to give students a glimpse into everyday American life outside the bustling cities.

The itinerary is simple: attend classes at the local high school, explore the town's history, meet American students, volunteer at community events, and experience a different culture firsthand. To help the visitors settle in, six local students have been selected as their guides—Ashlyn Banner, Aiden, Ben, Tyler and Taylor Hernandez, and Logan Fields.

To everyone else, they're just ordinary teenagers.

Reserved.

Funny.

Quiet.

Maybe a little strange.

No one knows they've spent months surviving a nightmare hidden from the rest of the world.

Every night at midnight, they're dragged into the Phantom Realm—a silent, colorless reflection of Alto where monstrous phantoms hunt anything alive. Seven hours pass there while only a single second passes in reality. Every injury suffered carries back into the real world, and escape isn't an option until dawn.

The exchange trip wasn't supposed to change anything.

But on Class 1-A's very first night in Alto, the impossible happens.

The rift opens wider than ever before.

Instead of only the six Alto teens being pulled into the Phantom Realm...

Every member of Class 1-A disappears with them.

Now two groups of students—future heroes and experienced survivors—must rely on one another to survive a place where bravery alone isn't enough. Quirks may help, but the phantoms don't fight by any rules, and every decision could mean the difference between everyone making it home... or never waking up at all.