In Japan in the year 2035, an accident known as the �Burst� occurs during a research project, spawning an out-of-control artificial life form called �Matter� that has spread throughout the Kurobe Gorge. The research city that was once hailed as the hope for humanity is cordoned off by the government. Two years later, 15-year-old Aiko Tachibana, who lost her family in the Burst, learns something unbelievable from Yuya Kanzaki, a new student at her school. A secret is hidden within her body, and the answer to the puzzle lies at the �Primary Point� that was the center of the Burst. Aiko resolves to infiltrate the restricted area, escorted by a team of divers and with Yuya as her guide.