Scout befriends a baby octopus who she finds on the shore, and names him Squish. She spends all her free time caring for him, teaching him tricks and forming a special bond. But when Scout has to go back home, she realizes she can't take Squish with her and has to leave him behind.
A young dolphin named Splash is curious about the humans who come to swim in the waters near his home. One day, he follows a group of humans back to their boat and is amazed by the world he sees above the water. Splash spends the day swimming and playing with the humans, but when it's time to go home, he knows he can't leave his family behind.
When nine-year-old Scout finds a secret passage leading to an underwater world inhabited by talking dolphins, she sets out to find the source of the pollution that is making the dolphins sick. With the help of her new friend, a dolphin named Fin, Scout must outwit a band of evil pirates and solve the mystery of what happened to Scout's grandpa.
Scout and Gwen travel to Florida to visit Scout's grandparents, and end up stumbling upon a group of poachers capturing sea turtles for their eggs. They spring into action to save the turtles, making new friends and discovering the wonders of the ocean along the way.
Nine-year-old Scout is shipwrecked on a remote island inhabited by dolphins. With their help, she begins to build a new life for herself. But when a group of humans arrives on the island, intent on capturing the dolphins, Scout must find a way to stop them.