Tanjiro, Genya, and Nezuko work together to try and kill the Upper Rank Four demon, Hantengu. Meanwhile, Misturi holds off the combined other body of the demon and its vicious attacks.
Tanjiro attacks the demon, but it grows in size and unleashes a sound wave on Tanjiro and Genya. It then jumps off a cliff with Tanjiro and Nezuko following. Tanjiro uses Hinokami Kagura to behead the demon, but unfortunately for him Hantengu's real body is within the heart of the bigger body. Hantengu then runs away and starts chasing three humans to try and eat them and regain his energy.
As the sun is coming up, Tanjiro has to make a choice though. Save Nezuko from burning to ashes in the sun since she's a demon, or go and kill Hantengu once and for all. Unable to decide, Nezuko decides for him by kicking him into the air. Tanjiro cries and then steels himself, using the new sword forged by Haganezuka and his Hinokami Kagura technique in order to behead Hantengu's real body once and for all.
Even though he's won, Tanjiro sinks to the ground, crying that Nezuko is gone forever, since she was the reason he started on this journey. However, the others tell him to look, and lo and behold, Nezuko is okay and is able to withstand the sun! Tanjiro says thank goodness and the day is saved.
As Mitsuri is about to run out of stamina and die, the other body of Hantengu fades to ashes since Tanjiro beheaded the real body. Mitsuri rushes to the others and embraces them in a hug, saying that they've won. Even Genya is impressed by Tanjiro's growth. Tanjiro and Nezuko then leave the Swordsmith Village among cheers from the crowd directed at Tanjiro for saving them. All's well that ends well.
Or is it??? Unbeknownst to Tanjiro and Nezuko, Muzan has learned of Nezuko's ability to withstand the sun and still be a demon, which is exactly one of the two things he's been looking for for one thousand years. And if he consumes Nezuko, he will become pretty much invincible.
What journey will our heroes go on next? Will Tanjiro be able to protect Nezuko? Only time will tell...