Bop and Grop take their grandsons, Declan and Chace, on an ocean adventure.
They enjoy the beach together, camp out, learn about some undersea creatures, and end up in a bathyscaphe that takes them down deep under water.
Will the dolphins they encounter help them make it back to the surface?
This book is number four in a series and is available on Amazon (eBook and paperback) and Apple iTunes (iBook).