Dolphins at daybreak /
by Mary Pope Osborne ; illustrated by Sal Murdocca. --
- New York : Random House, c1997.
- 67 p. : ill. --
- Magic tree house ; #9 .
"A first stepping stone book."
Their magic tree house takes Jake and Annie deep into the sea, where they meet up with dolphins, sharks, and octopi as they search for the answer to an ancient riddle.