"The Secret of the Unicorn" is a comic book adventure featuring the young reporter Tintin and his dog Snowy. In this story, Tintin discovers a model ship that holds clues to a hidden treasure linked to the legendary Unicorn ship. As Tintin investigates, he encounters various characters, including the villainous Sakharine, who also seeks the treasure. The narrative unfolds with thrilling chases and mysteries, leading Tintin to uncover the truth about the Unicorn and its connection to the past, ultimately revealing the treasure's location.