Tintin’s heart raced. “Chart?”
Tintin lifted it. The hull slid open.
Captain Haddock opened it with trembling hands. It was Sir Francis’s final testament—not a treasure map, but a confession. The Unicorn had been carrying not plunder, but a treaty that would have ended a secret war between two kingdoms. The ship was sunk not by pirates, but by a traitor in the Royal Navy. The three parchments were a decoy to mislead the traitor’s descendants.
“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. The Adventures Of Tintin Secret Of The Unicorn Serial Number
Calculus adjusted his hearing aid, which promptly whistled. “UN? That’s not a standard prefix for any navy, Tintin. But… wait.” He shuffled to a shelf and pulled out a crumbling registry: Royal Shipwrights’ Ledgers, 1670-1695 .
They crawled inside. The cave smelled of salt and ancient wood. And there, wedged into a stone cradle, was a final model—smaller, crude, made of driftwood. It had no sails, no cannons. Only a single serial number carved into its hull: .
“During Sir Francis’s time,” Calculus said, tapping a page, “the crown allowed private shipyards to use a code. ‘U’ stood for ‘Unicorn-class’—a fast frigate with a shallow draught. And the number…” He pushed his spectacles up. “The number was not the hull number. It was the chart number .” Tintin’s heart raced
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.
Tintin carefully removed the stern section. Inside the cavity where the rudder chain ran, he found not parchment, but a tiny brass cylinder, sealed with wax. He cracked it open.
Haddock squinted. “That? Just a builder’s mark. UN-7. Probably the toymaker’s batch number.” Captain Haddock opened it with trembling hands
Tintin smiled, closing the folio. “Sometimes, Captain, that’s the only treasure worth finding.”
The dusty air of Moulinsart Library smelled of old vellum and forgotten centuries. Tintin, his magnifying glass in hand, was not examining the grand tapestry or the carved oak beams. He was hunched over the model ship—the Unicorn —which sat on a felt cloth, its masts now splintered from the scuffle with the Bird Brothers.
They didn’t need the full map anymore. They had the serial number—UN-7—which told them exactly which Unicorn : not the ship, but the location. The wreck of Sir Francis’s Unicorn had been found by divers decades ago, stripped of its gold. But no one had ever searched for the seventh Unicorn —a sea cave, accessible only at low tide, marked by an iron-rich rock that bled red rust when wet. That evening, with Snowy barking at the gulls, Tintin and Captain Haddock stood in the cold Atlantic spray. The tide was out. The drowned church was a skeleton of black stones. And there, just as the silk said, was a rock streaked with ochre.
“Blistering barnacles!” Haddock bellowed. “The drowned church! That’s off the coast of Cornwall—St. Piran’s Old Chapel, swallowed by the sea three hundred years ago!”