Jill, the legendary warrior, started her adventure by tripping through a portal.

When Jill dropped out of high school two years before she graduates, she didn't think anything exciting would happen to her. That changes when she receives a letter from one of her friends asking for help. After investigating and learning that her friend is missing, Jill stumbles upon a portal. Having common sense, Jill turns back only to trips and falls through it anyway. On the other side, she wakes up in a mystic garden where a carefree girl named Chaersie explains that she has come into contact with the Yeither, and, as such, must now either stay here in the garden or go out and either hunt down Monseuteo, monsters from multiple dimensions created by The Garden Of Sinners, or risk being attacked by them while she is walking alone.

Jill decides to hunt them down and becomes a magical girl. Now, she must hunt down the Monseuteo and save her friend...if only it were that easy. The title says it all.