神社の娘、日暮かごめは神社のほこらにある古びた枯れ井戸から戦国時代へとタイムスリップしてしまう。かごめは、半妖の犬夜叉と運命的な出会いを果たし、あらゆる願いがかなうと言われている“四魂の玉”を巡る戦いと陰謀に巻き込まれていくことになる…。
Inuyasha's father defeated a powerful Chinese yōkai moth named Hyōga, five hundred years ago. The Shikon Jewel shard revives his son, Menōmaru, and his loyal servants, Ruri and Hari (who plan to avenge their family). When Miroku and Sango meet the duo, Ruri copies the wind tunnel and Hari possesses Kirara. Menōmaru kidnaps and places a spell on Kagome. He breaks the seal to release the power of his predecessor. Though becoming stronger, he achieves the title of the clan. While staying at the fortress, Menōmaru uses the spell to possess Kagome. Inuyasha attempts to evade Kagome, when he discovers that she is wearing Kikyō's clothes. Kagome inadvertently kills Inuyasha, pinning him with an arrow on "The Sacred Tree" (like Kikyō did to him fifty years ago). After Kagome resists the spell, she apologizes to Inuyasha. When Kikyō tells Kagome that she does not belong in the feudal era, she sends her to the "Bone-Eater's Well". A grief-stricken Kagome ends up returning in the present day and wanders though Tokyo. After sensing that Inuyasha is alive, Kagome shoots the arrow into the well, causing it to explode. She travels back in time and reconciles with him. As Kirara resists the spell, Miroku and Sango defeat the duo. When Menōmaru emerges from the moth cocoon and reveals his giant body, Inuyasha defeats Menōmaru with Kagome's help. With everything returned to normal, Inuyasha and Kagome spend time in Tokyo.
After the heroes seemingly defeat Naraku, Inuyasha, Kagome and Shippo are separated from Miroku and Sango. Kagura and Kanna meet Kaguya, the Princess of the Heavens, being sealed in a mirror. In exchange for freeing them, Kaguya promises them to grant their eternal freedom. When they take one of the five items, Kaguya is released from the mirror and she captures Kagome. The united group head and infiltrate the castle through the realm of mirrors. There, Kaguya attempts to transform Inuyasha into a full-fledged demon, but Kagome breaks the spell and saves Inuyasha. Naraku reappears on Kohaku's back, revealing that he faked his death. The villains escape from the realm. Kagome destroys the mirror and Inuyasha does to Kaguya's body. When Kaguya appears in a gas form, she is sucked into Miroku's wind tunnel. Inuyasha and his friends escape from the realm and return to their world through the mirror. With everything reverted to normal, they resume their journey.
Two hundred years ago, Inuyasha's dog-demon father saves his human mother, Lady Izayoi from Takemaru, a samurai who had yearned for her. Izayoi and her newborn half-demon son, Inuyasha, escape from the palace, where Inuyasha's father and Takemaru died.
In Horai Island, six half-demon children (Asagi, Dai, Roku, Moegi, Shion and Ai), watch a woman (resembling Kikyō) dropping a green orb to the Cauldron of Resonance. It frees the Four War Gods (Ryūra, Jūra, Kyōra and Gōra), and the scars appear on the rest of all children. Ai, not affected by the gods, leaves the island to meet up with Inuyasha and his friends. The heroes learn that Gōra used Kikyo's blood to create her doppelganger and Ryūra placed the scar on Inuyasha, though Inuyasha and the children cannot resist it. One man tells the story about the myth of the island, before Kikyō sets out to the island. As the rest of the villagers safely head to the shrine, Sesshomaru remembers the day he got the scar. Upon arriving at the island, Inuyasha and his friends are ambushed by Jūra. While Miroku and Sango manage to distract Jūra, Inuyasha saves Kagome and Ai from Ryūra.
幼少期に戦国時代と現代に離れ離れになってしまった双子の姉妹・とわとせつな。両親のことをほとんど知らないまま1人で戦国時代を生きてきた少女・もろは。人間と妖怪の血を引く"半妖"の少女たちが、戦国時代と現代、2つの時代を舞台に大活劇を繰り広げる！