Deep Palace is a prison island that houses only death row inmates. A young girl, Akari, was kept in the "Deep Palace" for a certain purpose... One day, the death row inmates suddenly start killing each other! A battle royale called the “Killing” is taking place where prisoners can do whatever they want as they remain the last ones standing! In the face of this pandemonium, will Akari be able to safely survive the "Killing" and escape from the prison?!