Harry the dog is very hot. All he wants is a nice shady spot away from the sun. But there's no more room under the family's beach umbrella - or anywhere else he looks. So Harry sits down sadly at the water's edge. Suddenly a big wave crashes over him, and when the wave rolls back, Harry is completely covered with seaweed. Now he's nice and cool, but everyone on the beach thinks he's a sea monster. On top of that, he can't find his family anywhere. What will Harry do now?