Life Game. "I want you to play a game. You have no choice in matter. I'll come soon". This was written in a letter that's received by the high schooler Seiya Hitotsubashi, who thought of it as a bad joke and instantly threw it into the recycle bin! He really has no clue that soon afterwards, he found himself waking up with a bunch of strangers in a sealed room... And they all ask the same questions...Where are they? Why are they there? And the most important thing is, how can they get out?!