The Beach Kids in Oceans of Trouble

Jazz Baker is just itching for an adventure. If she can't find one she will dream one up and make sure that her little sister, Lizanne and friends Sarah and Badger Marsky are included.
A few years ago the kids had discovered a secret cove near their hometown of Luna Beach, California. Every year Basil, a giant turtle that befriended the children, returns to the cove for a few days. The kids play games on pink sand and turquoise water while they wait for Basil's return.
One day they find two strange kids sitting in the cove. Jazz asks the two, Kat and Splitter, to leave. Thirteen-year-old Splitter doesn't like being bossed around by an eleven-year-old girl. He decides to go to Luna Park and make a bonfire for himself and Kat. Jazz warns him that the dry seasons of California can be dangerous for fires.
Later that night the kids and their parents hear a loud explosion from the park. Fire trucks rush to the scene! But Jazz just wants clues to prove who started the blaze. What clue does she find near the charred storage shed in the Park? Did Splitter do this terrible damage because of his dumb idea of a bonfire to show off to Kat? She must find him and convince him to admit his mistake.
How can the kids help Splitter without tattling on him? His reason for starting the fire shocks the kids and makes it hard for him to admit his part in the fire.
And when will Basil return to the Cove? Will they ever see him again? Will the Cove ever be the secret playground for Jazz and her friends again? But there is a surprise letter and an old friend waiting for the kids in the Cove at the end of their adventure.