On the first morning of summer, Pip ran down to the beach and almost tripped over her dog Biscuit. He had a green bottle in his jaws, washed up between two rocks. Pip pried it open. Inside was a paper torn down the middle: half a coastline in faded blue ink, and one word left at the rip. It said HARBOR.

Pip knew the old harbor. It was a twenty-minute ride up the coast road. She grabbed her bike from the porch, tucked the map in her pocket, and whistled. "Come on, Biscuit. The other half of this map has to be somewhere." Biscuit barked and chased after her wheels.