The Water and Insect Hashiras are off to slay another demon in accordance with their respective roles as slayers. However, this particular threat is like no other; it resides within the depths of an old sewage system. The two slayers must henceforth descend deep within the confines of this eerie setting to face their adversary head-on. On the way, though, they encounter many obstacles in both the physical and spiritual realms. #1 in Giyushino (Documented 3 April 2022)

Manga spoilers !!! After The final battle with muzan, the water piller lives a peaceful but boring life. As each day passes he starts to realize how much he cared for the hashira, especially shinobu. Soon after he starts feeling extremely guilty of not being able to protect them like sabito and his sister . However one night after he's fallen asleep , he suddenly wakes up in the past after a mischievous dream. He soon realizes he's in the past and has the chance to save his fellow hashiras and shinobu and more lives . The question is... can he do it ?