From Storm in Heaven:

The Prophet spoke of a day when the taking of human lives will lead to the end of the world, destroyed by an unending winter and a snow that covers the earth. Only by killing Kuroto, the harbinger of destruction, can the world be saved - and the only one who can do that is Hanashiro, the Savior. But when they meet, they discover that neither wants the role he has been given - and as they grow closer, they realize that neither wants to live in a world where only one of them can survive. But how can they overcome this fateful prophecy and their opposing roles in it? The last winter is fast approaching....

From the manga habit:

A dream filled with red camellia and the passing of a strange mask... The owner of this mask is a boy named Yue who lives in a temple populated with unusual - and not altogether human - residents.

It's winter, and the nearby town, Utsuwa, is holding a seasonal festival. Kurogitsune, Yue's fox spirit friend, decides it's the perfect opportunity for the sheltered young man to experience the sights, sounds, and (most of all!) the food in the outside world. Even though Yue is forbidden from ever leaving the temple, they sneak into town, not realising what they've set into motion.

Note: #10 is an extra volume. The main story ends in the 9th volume.