Winter has arrived once again in the tranquil lake region of Madguide Water. The tiny creatures who live there, Yarbi and his family, will soon be sleeping in their cozy bunks until spring. Legend has it that long ago, Yarbi's ancestors made a pact with the ancient "Ice Beast" that winter would be the season of the "Ice Beast." Worried about his friend, a two-spotted hoverfly larva named Yon, who lives in a hollow tree, Yarbi ventures out into the snow to check on him. Meanwhile, the students have left for winter break, and a ghostly commotion is unfolding at the boarding school where Utadori and his friends remain. The "mysteries" shared by Yarbi and his friends and humans—"Ice Beast," "Winter Soldier," "Beautiful Wandering Student," and "A Network of Underground Passages"—connect in unexpected ways, leading Yarbi and Utadori on an adventure. The long-awaited third installment in the series, following "Yarbi on the Shore" and "Yarbi's Deep Autumn.
