The Fish Book — Dory Lee Maske

Travel along on a raft down the Great River for a trip through time, a trip to the very beginnings of civilization.
Electra journeys to the Euphrates River, center of trade and turmoil in the medieval world, to uncover the truth of her ring's past.
In this final book of the Princess Electra series, Electra, Serafina and the twins, Esme and Shalin, encounter floods, earthquakes, thieves and buried cities in their efforts to uncover hidden secrets.