The morning begins like any other in Mikado City. Border Headquarters is bustling with activity as agents train, engineers fine-tune Triggers, and operators monitor the steady flow of Neighbor Gates. Nothing seems out of the ordinary.

That peace is shattered when every Trion sensor in headquarters spikes at once.

A deafening alarm echoes through the command center as monitors flicker with impossible readings. Instead of a single Gate, dozens of unstable rifts begin tearing open across the city simultaneously. Unlike normal Neighbor Gates, these fractures crackle with black and violet energy, distorting the air around them. Buildings bend unnaturally, streets ripple like water, and gravity briefly falters before returning to normal.

Operators scramble to make sense of the data, but the rifts refuse to behave according to any known Trion pattern. Some expand, others collapse, and a few drift through the sky as if searching for something.

Moments later, unfamiliar Trion Soldiers emerge—not from any known Neighbor nation. Their designs are sleek, obsidian-colored, and marked with glowing silver symbols. Rather than attacking civilians immediately, they spread throughout the city, as if searching for a specific target.

Border immediately issues a citywide emergency.

Tamakoma Second is dispatched to the largest rift, while other A-Rank and B-Rank squads race to contain the spreading incursions. As agents arrive on the battlefield, they realize something is terribly wrong: conventional Trigger attacks are weaker inside the distorted zones, communication systems cut in and out, and even experienced fighters struggle to keep their footing.

Far above the city, the largest rift slowly expands into a massive circular tear in the sky, its swirling darkness visible from every district of Mikado City.

For a brief moment, everything falls silent.

Then the rift pulses with an overwhelming surge of Trion, as though something—or someone—is about to arrive.