Apocripha/0 FANBOX Happiness Cage is an visual novel, developed and published by Stack, which was released in Japan in 2001.

An angel falls from Heaven to the Abyss, and here he cultivates a kingdom, the kingdom of Hell (Naraku), becoming the King of Hell. He tries to build a beautiful land, but it can never reach the beauty of Heaven: the demons live in troubled times, being attacked by fallen angels who survive the fall to the Abyss, fearing the bloodshed caused by these insane former angels against them. The King starts to become weak and tired, and with his last power, he gave birth to two new hopes: a prince with golden hair born from his red right eye, and a price with silver hair born from his blue left eye.

The King decides that the two twin prices, Alex and Platina, are to fight each other, and the winner who proves his power will become the new king of Hell, while the loser will face death. As such, Alex and Platina, who never even knew each other, are thrust into a battle against each other, and the future will change depending on the outcome.

Now find out what happened behind the scenes, before the battle for succession was to take place...