TV-Series
Description
Jean Roque Lartigue is the young male protagonist of the series. He is a fourteen-year-old orphan living in France during the late nineteenth century, specifically around the time of the 1889 World Exposition in Paris. His father was a wealthy ship captain and trader who was lost at sea prior to the story's beginning, a loss that Jean has not fully accepted, as he clings to the hope that his father might still be alive.

Jean is characterized by a personality that stands in stark contrast to the more pessimistic and distrustful Nadia. He is depicted as highly generous, patient, friendly, and genuinely well-behaved, often displaying a level of optimism that helps lift the spirits of those around him. His natural curiosity and dedication are most evident in his great love for science and invention. Despite his genius-level intellect and capability to create complex machines at a young age, he is notably awkward when it comes to social graces, particularly with girls. He can be oblivious to romantic cues and is prone to becoming so engrossed in his work that he neglects other matters, which sometimes leads to misunderstandings with Nadia. Nevertheless, he is consistently brave, loyal, and honest, possessing a strong moral compass that even his adversaries find admirable.

Jean's primary motivation at the outset is twofold. He is immediately driven by a deep infatuation and growing love for Nadia, whom he first sees by the docks in Paris. He is also motivated by a personal desire to find his missing father, a goal that becomes intertwined with the larger adventure surrounding the mysterious Blue Water. As the story progresses, his role evolves from a boy trying to win a girl's affection to a crucial and courageous member of the group. He uses his inventive skills repeatedly to help his friends escape dangerous situations, such as when he sacrifices his own flying machine to rescue Nadia from the Grandis Gang. His technical abilities become vital assets aboard the submarine Nautilus, where he contributes to the fight against the primary antagonist, Gargoyle.

The most central relationship in the series is the one between Jean and Nadia. Their connection begins as a rescue romance, where his persistent kindness and repeated acts of heroism gradually earn the trust of the initially frosty Nadia. Their relationship is complex, marked by genuine affection, frequent disagreements over philosophical issues like technology versus nature, and Nadia’s emotional outbursts, which Jean continually endures and forgives due to his deep patience and understanding of her troubled past. Through his unwavering support and optimism, Jean plays a crucial role in Nadia's personal transformation, helping her become more trusting and caring. He also forms bonds with other characters, such as the engineer Hanson, from whom he learns to accept help and collaborate on complex projects.

Jean undergoes significant personal development over the course of the narrative. Initially, he harbors a naive belief that technology is an unalloyed force for good, a viewpoint that is challenged when he witnesses the destructive power of the Nautilus as a killing machine and suffers personal tragedy. A key aspect of his growth involves learning to temper his fierce independence; he is forced to realize that accepting assistance from adults is not a sign of weakness but a valuable part of maturing, particularly when building his helicopter. His time stranded on a deserted island forces him to take on the responsibilities of a provider and caretaker for Nadia and the young Marie, further accelerating his path to adulthood. Throughout filler episodes, his character remains a consistent anchor of patience and loyalty, even when other characters' personalities fluctuate.

Jean's most notable ability is his extraordinary talent as an inventor and engineer. Despite his young age, he is capable of designing and building advanced machinery, including a functional flying machine and a helicopter, using the technological standards of the late 19th century. His inventive prowess, combined with his courage and quick thinking, consistently proves to be the key to overcoming the many physical and mechanical challenges the protagonists face on their journey.