A stranger comes to a fishing village, which plans to catch lots of fish through poisoning the river.  As the villagers debate, they are warned against this by a traveling priest. A fisherman saves a little turtle and is taken to an undersea palace. Two boys go to ask the fire god to help them with a demon who's been raiding their village.
This treasure box is proof that 
you were here at Ryugu Palace,
Esta caja de tesoro prueba que usted 
estuvo en el Castillo Ryuuguu,
Con esta caja tamate recordará 
que estuvo en el castillo Ryuuguu.