Half-demon twins Towa and Setsuna are separated from each other when a mysterious tunnel sends Towa into the future, where she is found and raised by Kagome Higurashi’s brother Sota.

In the present day, a demon emerges through the Sacred Tree at Higurashi Shrine with Setsuna, Towa’s twin, and the bounty hunter Moroha in tow. Towa, Setsuna, and Moroha struggle to battle the demon, whose powers have been strengthened with two Rainbow Pearls, but seeing Setsuna in trouble awakens Towa’s latent demon powers.

Towa decides to return to the feudal era to help Setsuna regain her memories. The trio enter the corridor leading to the feudal era, but within it awaits the spirit of a certain priestess.

Zero removes the seal that Miroku placed on Setsuna to suppress her demon powers, awakening the latent demon blood within.

Setsuna and Towa hire Moroha to help slay Zero. The trio successfully track Zero down, but Riku stands in their way.

Zero unearths Towa’s sadness about growing up in the modern world and corners her with her memories of loneliness and suffering. Sesshomaru appears before the demon slayers and commands Setsuna to pay the Tree of Ages a visit.

Osamu Kirin brings the Grim Comet to the feudal era. He convinces Rion that they are both hoping for the same world and promises to make it a reality. Meanwhile, Towa, Setsuna, and Moroha are stuck in the present day.

The feudal era is saved from the Degenerate Age. Inuyasha helps repay Moroha’s remaining debt. Towa and Setsuna receive kimonos from their mother, Rin. Towa, Setsuna, and Moroha accept a demon-slaying request from a mysterious man.