"Tiannan Academy" is a top-tier school famous for nurturing talent.
Every year, it scouts high school students who are active in various fields from different schools, and before long, they came to be known as "Ultimates."

Because merely entering this academy is practically a guarantee of success, the students of Tiannan Academy's 80th class enrolled with those hopes and dreams for the future.
However, the moment they set foot in the school, they were suddenly struck by intense dizziness for some reason.
When they woke up again, they were in an unfamiliar place. Furthermore, outside the windows was an expanse of dark sea.

After a while, a mysterious shellfish suddenly appeared in front of everyone, unilaterally told them some incomprehensible things, and then vanished.
—"If you can overcome the killing game, you can escape from here."

A crisis looming right before their eyes. What will become of the fates of these sixteen people!?

[Translated from Official Site]