Barnaby, Tintin, and Sakharine first met in the market in Brussels wanting to buy the model ship resulting in Tintin buying it first. He is then later seen trying to warn Tintin and betray the the Bird Brothers but is shot while trying to do so. Later in the book, he woke up in the hospital and told Thompson and Thomson and Captain Haddock where the Bird Brothers were located, resulting in their capture.
Animated Series Version
He first crosses Tintin while trying to purchase his model ship of The Unicorn off him. He was a collaborator with the Bird Brothers, who were seeking the parchments inside the three identical models of the Unicorn. Barnaby was later shot when he tried to betray the Bird brothers by revealing their plans to Tintin. It was later revealed by the Thom(p)sons that he survived the shooting and given a statement against the Bird Brothers.
Barnaby was reimagined in the film The Adventures of Tintin: The Secret of the Unicorn, playing a much more aggressive character for the audience. He is still featured despite the absence of the Bird Brothers as the main antagonists and instead appears in a more heroic role. Barnaby gave Tintin the clue leading him to the Karaboudjan before he died. His full name in the film is Barnaby Dawes. It was later revealed by Thompson and Thomson that he was actually acting as an undercover FBI agent working alongside Interpol . He was voiced in the movie by actor and comedian Joe Starr.