The stage is set on an ocean oilfield base, Seraphix. A hell that tries to imitate the Holy Grail War of the Moon. A pleasure prison that you can never escape from unless you're the last one standing. There's not much time until it reaches the limit and collapses. What lurks within the depths of the "Ego" that desires to dance --- This is the adaptation of the Epic of Remnant Chapter 1.5 from the mobile game, Fate/Grand Order.