You see the title. You know good and well what the formula is, don't you? A new killing game, with 16 peculiar characters trapped in a set location, soon to be killed off one by one via the will of a despair-obsessed bear. Well, in that case, will this new generation story replicate that? Not exactly. This killing game's a bit bigger, a bit better, a bit less of the grandeur and adequacy of the students' living standards. A bit less of the mercy that befitting "Ultimates" so "rightfully" deserve! More than that, it includes me, Monosūta. And who can resist a charming little devil like me? You better not. I'm the king of this world, superior to any bear or cat or whatever-the-hell descendants. I decide your future. Maybe a little restricted by the growing audience, but I'm more than capable of making them all BEG and TREMBLE for mercy! Why don't you come and see how? See what this killing game's really about...
The Ocean...How would it exactly feel to be able to see the fish, the sharks and everything else..without even dying while underwater..Well, even if such a thing cannot happen...Aquariums still exist for that purpose. But...when a new Aquarium releases...so does a story to reveal.
Mysterious Lake Aquarium...A new Aquarium that has just opened up in Japan, and was open for many people on the very 1st day! Around those people, were 16 Ultimates who were each on their way there...but something happened, which changed everything.
Follow into the steps of our dear protagonist's point of view, as they suddenly wake up in a rather strange place with 15 strangers without even knowing what is going on! Where are they exactly? What is going on? How did they even get there? All of this, you can find out in....Gacharonpa! Aquatic Despair!