Days with My Stepsister, Vol. 6 (light novel) - Eriko Sugita, Hiten Hiten, Ghost Mikawa

Infected by the magic of Halloween night, Yuuta and Saki sought out each other's warmth. Though it might look the same to those around them, their relationship has undergone a definite change. As they pass their first winter together, including its various celebrations, they struggle to balance communication and the joy of surprise. How can they make each other happy, and where are they headed? Are marriage and children in their future, or something else entirely?