Ryuujinnuma

A young boy named Takuya discovers a mysterious glowing stone in a forest near his home. The stone leads him to a hidden world beneath a lake, where he encounters a dragon that has been trapped for centuries. Takuya learns that the dragon is connected to an ancient legend about the lake and its guardian spirits.

As Takuya spends more time with the dragon, he realizes that the creature is suffering and that the balance of nature is at risk. He must find a way to free the dragon and restore harmony to the land, all while keeping the secret of the hidden world safe from those who would exploit it.