$USDC Old Chen goes to the abandoned lighthouse every evening. The caretaker says it's haunted, but he always arranges three pebbles in a wooden box on the top floor. Until the demolition team excavated a rusty iron box, and the yellowed letter paper revealed blurred writing: "On the night of the typhoon in 1943, hide the three milk teeth of my daughter." Old Chen suddenly coughed violently, and in the palm of his hand lay a blood-stained molar - he had guarded the lighthouse for sixty years, which was originally the coordinate to guide his lost daughter home.