Once out of the house of the demon who controlled the drums, Tanjiro finds himself in front of Zenitsu Agatsuma while he is being beaten by the young man with the boar's head. The boy immediately steps in to stop him, but a surprise awaits him... After a short break, Tanjiro's group receives an urgent order from the Demon Slayer Squad and heads towards a strange mountain. What could be hidden in that place?