Our stage this time is the Mukawa River that flows along the Pacific side of Hokkaido Prefecture. Among kayakers, it is renowned as one of the most outstanding rapids in Japan. In spring, a kayaker who has acted as a river guide on famous raging rivers in the world is taking on a challenge to kayak along the raging river swollen with snowmelt, testing his skills and judgment. He experiences the rich nature in Mukawa, weaving his way through the boulders in splashing waters. Later, we also show you footage of the wild creatures that live in the upper reaches of the Mukawa River.