Above the village of River Valley there is a rock with the face of a man with a legend: when it turns its face toward the lake, the village would be destroyed.
In this episode a strange accident sets off a mystery involving a powerful man-made solar sphere, which attracts the attention of the detective Randolph Holmes.
Lots of people find notes in bottles, but one day Astro Boy finds forty-three of them, all from a girl named Lily who is being held with her father on a strange island named Peligro.
The old D51 steam engine doesn't seem much more than a museum piece when Astro Boy and his class see it on their class field trip, but when a violent storm hits and threatens to burst the old dam up river, the engine sure comes in handy.