One day, Guest received a ticket for a 4-day, 3-night cruise on a luxury liner from their lazy friend, A-kun. It was apparently in A-kun's mailbox, but he was too lazy to go. Thinking it would be a dream to stay on such an expensive plan, Guest decided to board the luxury ship.

"You should go, since you have the chance." "I want to thank you for everything you usually do."

The luxury liner for this trip is called the Empty Box. It sounds familiar, but oh well. It's large and has a great atmosphere; it's going to be the best cruise ever.

Wait... something is wrong with the ship...

I have to get away!! I have to escape! It's all A-kun's fault!!

Someone, help me...

『It's okay, you aren't alone.』

Do you want to get out of here? Or do you want to become like them?