Nezuko prepare for battle!
Nezuko is on a mission with Tanjiro and the others and she gets separated from them. She manages to find the demon and prepares to fight it. She also signaled her Kasugai Crow to warn the group to find her immediately. As Nezuko draws her reddish-pink nichirin sword, she preys and hopes that the others arrive soon.
FYI: She's fighting a member of the Twelve Kizuki, Lower 4 to be exact. This is an extra arc where Tanjiro and the others fight the other lower ranks of the Twelve Kizuki.