Twin boys, Takashi and Satoshi, are playing in a forest. The energetic Takashi talks the shy Satoshi into climbing a large tree, but as they do, Satoshi recalls something that had vanished from his memory.

Yurika is traveling with her friends from college. The group finds themselves at a waterfall deep in a forest that wasn't mentioned in their guidebook, and they hear what sounds like objects falling over the roar of the water.