Finn has always been different, and in the tiny fishing village of Stromhead he sticks out like a sore thumb. Always told to keep away from the water, he's felt that something was missing until one day he dives in and finds that, swimming with the dolphins, he feels completely at home.

But his new friends are in danger of being injured
by the rubbish that floats out into the water - and
now a supermarket is going to release thousands
of balloons that could drift out to sea and cause
even more damage. Desperate to help the
dolphins, Finn goes to the Lighthouse Crew, a
group of kids who have always left Finn out. Will
they be able to set aside their differences to save the dolphins? And what will Finn discover about his past along the way?