The story is set on a drifting spaceship.
After an unknown enemy, "Gnosia," a being that disguises itself as human to attack humans, has infiltrated the ship, the crew decides to vote for one suspect each day to put into cold sleep.
If humans can put all the Gnosia into a cold sleep, they will win.
On the other hand, if they fail to identify them, the crew will be attacked.
As they all try to make the right choice, the protagonist, Yuuri, finds themselves in a situation where, no matter what choice they make, they return to the first day.
Will the crew be able to make the right choices?
What is the secret hidden within the time loop?
And what are the hidden sides of the crew members that will come to light?
Now, the curtains rise on a story that feels like a short time is repeating and is simultaneously eternal. Have a good trip.