This game is based on the Chaos Lineage Drama CD series.

When the church bell rings, new “gears (fate)” set into motion—.

A world where there are only 13 vampires and you, the “Legendary Eve.” The vampires had continued to fight over you in order to become the “Demon King” that reigns above all. Scarlet, Violet, and Orange—the vampires divided into three houses, but you feel a strange sense of intensity. And then you remember.

—Who you are, and who they are.

The vampires whose memories have gone astray, who forgot their original selves and live with false brethren. They accept this situation as reality. No matter how much you try to appeal to them, your words do not reach them. Your beloved, their memories with you forgotten, heartlessly draw near. Every day, you have no choice but to watch them kill each other, blood-lust and snarling. In this closed world with no escape, can these broken gears really be stopped? This is the twisted “Blood Lineage” of the vampires that you follow.

After countless failed attempts, Karlheinz finally thinks that his “Eden Project” has been sucessful and begins to make plans to bequeath his powers to his sucessor & fade from existence. However, his longtime friend & chess partner Socrates isn’t quite convinced that Karlheinz’s chosen Adam & Eve are up to the task. To test the pair’s love is true, he decides to trap all of the guys & Yui in a world that he has created, as well as wiping all of their memories.

Inside the fake world, the guys are seperated into three families – Orange, Scarlet & Violet. The families have been locked in a battle to the death in order to decide who will become the “Supreme Ruler”. The key to this is the legendary “Sleeping Princess” called Eve whom will, the legend foretells, appear in the church one day. With all the players set, this deadly game of survival begins, will Yui & the guys ever get their memories back so they can return to their own world?