What happens when you're locked in a room when you can't leave without a kiss~1

During a walk outside in the woods at midnight, Muichiro and Nezuko encounter 2 demons. After defeating them, both are covered in blood, excluding Nezuko, who has healed. They decide to head back. But before they can even get two steps away, Muichiro suffers a sudden transformation into a demon. (it wasn't the demons' blood, it was Nezuko's). Nezuko is desperate to keep Muichiro away from the Hashiras and other Demon Hunters. But it's not long before the Hashiras find out...