The next morning, he visited Professor Calculus. The half-deaf genius was calibrating a new ultrasonic depth-finder. “Calculus, does ‘UN-7’ mean anything in naval history?”
“Perhaps,” Tintin said, but his eyes were sharp. He pulled out a notebook. The same number—UN-7—was etched inside the cannon’s barrel. And again, on the underside of the stern gallery. Three times. Deliberate.
Tintin’s heart raced. “Chart?”
Inside was a sliver of silk. On it, in Sir Francis’s own hand: The seventh Unicorn sleeps where the tide writes its name twice a day. UN-7: follow the old pilgrim’s path from the drowned church at low tide. The rock that weeps iron is the door.
That night, Tintin couldn’t sleep. He stared at the photographs of the three parchments. Sir Francis Haddock’s log entries were clear: Latitude. Longitude. Three keys. But the number UN-7 scratched at his brain.
Tintin lifted it. The hull slid open.
Haddock looked at Tintin, his eyes wet. “All that trouble. All that danger. For… justice.”