Their next destination is to the north-northwest. Tanjiro and Nezuko head towards Mount Natagumo with Zenitsu and Inosuke. This mountain is covered with spider webs and is swarming with innumerable spiders. Leaving the cowering Zenitsu behind, Tanjiro and Inosuke head up the mountain where they run into fellow Demon Slayers entangled in spider webs.

Tanjiro and Inosuke battle the Demon Slayers trapped by spider webs. After slashing the threads and destroying the webs, they head deeper into the mountain. The farther they advance through the forest, the thicker the threads become, and those under their control start moving in ways impossible for a human being. Stopping the Demon Slayers without hurting them isn't going to be easy, but then Tanjiro makes a certain move...

Tanjiro and Inosuke face off against the Father Spider Demon of Mt. Natagumo. Tanjiro unleashes an attack, only to get hurled away by the demon's overwhelming power. Landing near a river, he comes upon the young demon Rui torturing the Sister Spider Demon. When Rui calls their bond of terror and hatred "a family’s bond," Tanjiro is enraged. So begins the battle between Rui and Tanjiro.

Swordsmen in the Demon Slayer Corps known as Hashiras have arrived on Mt. Natagumo. Giyu Tomioka, the Water Hashira, slays the Father Spider Demon with a single strike. Inosuke, thrilled to see such a display of swordsmanship by someone in a totally different league from himself, challenges Giyu to a duel. Meanwhile, Zenitsu lies near death as the poison circulates throughout his body. Just then, the Insect Hashira, Shinobu Kocho appears before him.

When Rui assaults him with his Blood Demon Art, Tanjiro braces himself for certain death. As his life flashes before his eyes, he suddenly remembers his father's dance, the kagura, and unleashes a new, non-Water Breathing attack. Hinokami Kagura Dance. Knowing that he’ll be receiving a simultaneous blow from the demon, he uses his new move to slice off Rui’s head. As Tanjiro crawls towards Nezuko, who lies on the ground, riddled with wounds, someone appears before him.

Seeing Tanjiro try to protect Nezuko even as he collapses triggers memories of Rui’s own past. Once a sickly boy, he became a demon after meeting Muzan Kibutsuji who gave him a share of his blood. But after he turns into a demon, his own parents try to kill him. Ever since then, he has been searching for a family. Seeking a bond that he can never hope to acquire...