One day, without any warning, the ground in the middle of the city collapsed. At first, it was thought to be a massive sinkhole. Roads cracked, buildings tilted, and subway tracks and water pipes collapsed all at once. However, the collapse was deeper than expected. Beneath the crumbled ground, there were no underground cavities, subways, or abandoned facilities. There was only a vast hole of unknown depth.

People called it 'The Hole.'

What emerged from the Hole was difficult to even call a living creature. It had no form. No color. Nothing was captured on camera. Yet, it clearly existed.

People called these 'Anomalies.'

When they pass by a person, goosebumps suddenly break out on the skin. The hem of one's clothes flutters in a space without a single breath of wind. And in the places they pass, people lose their sense of direction for no reason or lose their memory for a short period of time.

And a few seconds later—

People collapse. Some died, and some survived. The government and military sealed off the area around the Hole. At first, it was a disaster response. Later, it became a military operation.

Thus, the Spatial Anomaly Response Unit (S.A.R.U.) was formed.