Captain Nemo: The Fantastic History of a Dark Genius

Blurb

The novel follows Verne and André Nemo from their childhoods. Verne is depicted as being a sheltered, almost neurotic individual who is incapable of taking risks, while Nemo is adventurous and resourceful, especially after the death of his father. Both lust after the independent-minded Caroline Arronax.
The two boys attempt to apprentice themselves to a ship captain named Grant, but Verne's stern father finds him and forces him to come home and study to become an attorney. However, Nemo joins the crew, and after an attack by pirates, is stranded on a mysterious island. Meanwhile, Caroline is forced to marry an explorer, Captain Hatteras. Eventually Nemo manages to escape through a fantastic underground world. Returning as a hero, Nemo proposes to spend five weeks in a new balloon design exploring Africa. Caroline joins him, but Verne, fearing what might happen, refuses.
Nemo volunteers to fight in the Crimean War. While there, he is taken captive by one of his supposed allies, an Ottoman commander named Robur. Robur is engaged in a power-struggle with a rival official, Barbicane.