Five thousand years ago, there was an organization called the Dark Shadow Defenders who gathered evil witches, alchemists, sorcerers, wizards, swordmasters, and mages from all over the world to bring about the destruction of Earth and make it their planet that ran according to their rules and codes of conduct. The most powerful guardians of the world residing in a magical realm called The Hundred Heavens, the Heavenly Spirit Guardians of Fire, Water, Earth, Wind, and Light, had gathered together and summoned the chosen maiden born and blessed with the powers coming from the rare Celestial Five Lights Shower. This chosen maiden was to become the most powerful warrior of all by accepting to be a special vessel of all the five Heavenly Spirit Guardians' holy powers, combined with the Light of Hope exclusively existing in her heart, which allowed her to become what the ancients would call as the Priestess of Life.

With the help of the Heavenly Spirit Guardians, she defeated the forces of the Dark Shadow Defenders and sealed them in the darkest and deepest magical dimension of the Earth, only known as the Tareus Dimension. But upon doing so, the Heavenly Spirit Guardians didn't realize that sealing them and ensuring their security resulted in the death of the Priestess of Life. It appeared that she used the entirety of her life force to seal the enemies. Soon after, her soul, along with the remnants of her powers, traveled through space and time to make sure that the seal wasn't broken. The Heavenly Spirit Guardians concluded that their battle might not be over as they hoped it would be. With that terrifying conclusion, they decided to send large parts of their powers to accompany the wandering soul of the Priestess of Life in completing the immense task, passing the soul and the Heavenly Spirit Guardians' powers on from one human incarnation to another.

In the present day, an innocent child's prank inevitably caused one of the five Tarean seals to be broken. Now armed with an even more powerful evil force, the released Dark Shadow Defenders (collectively known as Tareans) decided to continue the halted plan of destroying Earth once again. But the Priestess of Life had already anticipated this moment long before her immediate death. Chosen by the soul of the Priestess of Life and bearing the mystical powers of the 5 Heavenly Spirit Guardians, chosen people must fulfill an ancient mission of obliterating the destructive forces of darkness once and for all before the feared ultimate annihilation of the world becomes a reality.

Joining forces to do the task of saving the world was biker Hiwara Shuichi, photographer Mizuhashi Eichirou, composer Hoshiyama Itsuki together with his pianist sister Erika, and archer Fuumiya Misae. It wasn't long before they accepted their duties as Seitengers. Later on, a traveling novelist named Tennouji Helen joins the team. Accompanying them in their journeys and mission are historian-cum-restaurant chef and owner Mizuhashi Hideoki (Eichirou's father), book store owner Kinmura Nanami and her son Akira (Eichirou's aunt and cousin in the second degree of consanguinity respectively), amateur photographer Tsukimori Kanako (Eichirou's childhood friend) along with her cousin Takeda Natsume and her father Tsukimori Genma, Shuichi's best friend Raisaki Amuro, Amuro's former politician father Raisaki Shotaro, Misae's senpai Furukawa Nika, Misae's childhood friend and butler-in-training Kanagi Haru, Helen's writing mentor/guardian Kuraki Makoto, and Helen's editor/older sister figure Asakura Minako.