Two brothers have a river trip. Along the way, they see silhouettes of birds, deer, and crocodiles from far away, but it turns out to be water plants, wood, and rock when getting closer. And they wander if there is a monster under the river. Because of the big fog, they return back, and all those animals they see silhouettes actually show up. As for the monster, it's also there but they did not find out. This is an adventurous river trip with visual illusions. What you see may not be true.