If you want to experience the "serial number" easter egg yourself, follow this guide for the (the only version where the feature still works post-server shutdown).
Click on the three horizontal lines icon in the top-left corner, then choose "Activate a key" .
Because the game was released in 2011 and is no longer available on many primary storefronts like Steam, you can obtain a legitimate serial number through several third-party retailers: Ubisoft Connect (formerly Uplay): Most available digital keys are designed for the Ubisoft Connect client . Retailers like AllKeyShop often list keys for this platform. Physical Retail Copies: The Adventures Of Tintin Secret Of The Unicorn Serial Number
The PC version of The Adventures of Tintin was designed to be activated digitally. This means that even if you bought a physical copy, you were likely given a 16-character to 20-character product key that needed validation via Ubisoft Connect.
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. If you want to experience the "serial number"
“The Unicorn was a secret vessel. Her true logbook wasn’t kept on paper. It was kept in her bones. Each ‘UN’ part—the bowsprit, the rudder post, the keel—had a number. UN-1, UN-2, all the way to UN-7. The serial number you found is a coordinate key. UN-7 means the seventh structural point. If you know how to read it, it points to a hidden compartment.”
Includes a local co-op mode where you play as characters from Haddock's dreams. Retailers like AllKeyShop often list keys for this platform
Are you having trouble a physical key, or is the code not working when you enter it? The Adventures of Tintin: The Game - PCGamingWiki PCGW
If you purchased the game digitally, the serial number is usually sent via email, found in your account's order history, or in the "Library" section of the store where you bought it.