Crystal of Storms (Fighting Fantasy: Scholastic #17)

An astonishingly imaginative, edge-of-your-seat adventure – part story, part game!
You, the hero of this story, are a member of the Sky Watch keeping the floating archipelago of Pangaria safe.

When the Nimbus isle suddenly crashes out of the sky into the Ocean of Tempests below, you must explore the remaining islands, and battle both storms and sea beasts in your mission to raise Nimbus from the deep.