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.

Mr. Alvi held the map to the light and laughed. "My grandfather drew this. He split it in two and hid the halves so only a real adventurer could join them." He pulled a dusty tin from under the counter. "This half has waited forty years. Go on, fit them together."