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 decided to ask a grown-up first. She biked straight to Mr. Alvi's bait shop at the pier, where the old sailors traded stories. If anyone knew about a torn map and a word like HARBOR, it would be the man who had fished this coast for fifty years.