It starts as a Jules Verne romp with a circus girl and a lovestruck kid inventor, and then it quietly starts taking your heart apart. Nadia is not a sweet heroine, she is stubborn, self-righteous, cruel to Jean about his meat-eating and his optimism, and the show makes you sit with that until you understand why. Anno's fingerprints are everywhere: Nemo's guilt, Electra's grief, Gargoyle's masked contempt for human weakness, and a Nautilus that costs something every time it wins. The animation in the first stretch and the final act is Gainax firing on everything, all sweeping undersea light and genuine spectacle. Yes, the Island and Africa arcs are a slog of bad gags and stalled plot, and yes, you push through them anyway. Because Marie and King and the Grandis gang have already adopted you by then, and the ending earns every tear it takes.

In 1889, the world stands at the peak of a great age of technological discovery. A sinister figure called Gargoyle, fixated on returning the old Atlantean empire to its former glory, sets in motion a plan to conquer the world. Nadia joins forces with Jean Raltique, a young inventor, and the mysterious Captain Nemo of the submarine Nautilus to stand against Gargoyle and Neo-Atlantis and save the world. Inspired by Jules Verne's novel '20,000 Leagues Under the Sea', the series blends adventure, comedy, romance and science fiction.