to Z Mysteries Super Edition #7: Operation Orca

Thar she blows! Dink, Josh, and Ruth Rose are on an Alaskan whale watching adventure. On their first day, they see a mother orca and her calf. But the next day, the baby orca is missing! The calf needs its mother’s milk. Can the kids solve this whale of a mystery?
 
The alphabet is over, but the mysteries continue in this seventh A to Z Mysteries Super Edition, featuring a 26-letter secret message...