Fena Houtman is a young orphan girl that has been raised on an Island where there is no hope of becoming anything more than chattel, to be used and discarded by soldiers of the British Empire. But Fena is more than just another powerless orphan. When her mysterious past comes knocking, Fena will break the chains of her oppressors. Her goal: forge a new identity, free of bondage, and search for a place where she can truly belong and find out the true mysteries behind a keyword "Eden." It is the story of a lifetime adventure she and her crew of misfits and unlikely allies will have, in pursuit of her goals!

Years ago, extraterrestrials known as the Citizens of the Stars descended upon the planet of Tokinea and wreaked havoc on humanity. To fight back against them, the military developed the Majin project to create hybrids between humans and the Citizens of the Stars. With this combination of genes, they hope to exploit both the subservience of man and the powers of the alien. Majin no.7, a young girl kept under lock and key in a military base, is released after the Citizens of the Stars launch an attack. Despite possessing a plethora of abilities capable of effortlessly eliminating the enemy, she is burdened with doubt on the battlefield. However, when a boy named Yuuri tells her that she must fight to earn her freedom, Majin no. 7 is inspired by his courage and defeats the remaining Citizens of the Stars. The two decide to embark on a journey together, determined to find their calling in a time when humanity knows no peace.

Mio has feelings for her childhood friend Arata, but can't convey her feelings. One day, as they continue their delicate relationship, the two fight over something trivial. After letting tensions settle, Mio goes to make up with him in the pouring rain. While on her way, she gets into a traffic accident. When she regains consciousness, a mysterious and unfamiliar world appears before her eyes.

The Eto Rangers ride in Space-Time Transmitting Machine Kirinda to repair the Novel Worlds of Mugen. The Eto Rangers themselves are anthropomorphic animals, each representing one of the 12 Chinese zodiac animals (and The Twelve Branches in Buddhism). In Japan they are known as the Eto animals. The Novel Worlds are stories created by the human imagination, such as old folk tales as well as newer books. These living worlds play out repeatedly, and are necessary for the good of humanity. Princess Aura rules Mugen, which is an island continent hanging over an ocean from the skybound Novel Pole. The Great God Goal gives her power, but she may never leave the small palace island area. Their nemesis is the forgotten Spirit of Cats, Nyanma (real name, Chocolat), who was excluded from the choice of 12 protectors by being disqualified from the race (in actual legend there are many versions of this story). She seeks her revenge by distorting Novel Worlds with Jarei Monsters. When a Jarei Monster goes to a Novel World they alter the story, turning it into a different version, sometimes a parody of itself. Bakumaru, the Spirit of Mice, must use the Genmakyou mirror to reveal ("Jarei Shouran!") the evil spirit once enough clues lead to its identity. Often the Eto Rangers must play out some of the story to find out who or what it is, sometimes even taking on the role of one of the characters in the tale. After defeating the creature, Kirinda is called when Bakumaru holds up his hand with one of Aura's 12 gems on it and calls out "Daikourin Kirinda!" Kirinda descends from a dimensional slit and purifies the evil spirit with a beam weapon, calling out "Jouka!" (Purification).