On a Sunday, Ruru suddenly shows up. A couple in a long-distance relationship, finally spending time together after a long while. Sharing home-cooked meals, playing cards, taking baths together... Ruru is usually bright and energetic, but occasionally reveals a more serious expression that tugs at the heart. Her unexpected visit holds an important reason. Filled with sweet and bittersweet moments of sincere and pure affection, this is a special Sunday where their bond grows even deeper.