In the Kingdom of Valdia, the Princess is kidnapped by demonic forces of the Realm of Besek, known as Majin. It is also said that the Majin guard a secret treasure, the Eternal Poison. Responding to the King's call, many adventurers head off to the Princess' rescue, but what are their incentives, and is it really the Princess they're looking for?

Eternal Poison, also known as Poison Pink, is a strategy role-playing game by the Summon Night series creator, set in a dark fantasy/gothic environment. In the same vein as most tactical RPGs, battles are performed in turn-based style, in a grid-based battlefield. The player may choose to battle demons or to capture them in order to use them as allies in his party. Returning to his base, the player may purchase weapons, build up his army and customize his "Majin" or transform them to special items. The story is told from the perspective of five different parties, and the choices made can define the outcome.