First major departures from the book happened in this episode:

The Count encounters Jacopo in Marseilles and frees him from an officer of the law rather than meeting him and his smugglers on an island and claiming to be shipwrecked.

The Count tracks down Caderousse, interrogates him about the letter from his file, and hires him to be a spy in Paris in order to earn forgiveness for his part in allowing Edmond to be arrested (which was essentially just staying silent). It seems that Caderousse will not be the thieving cad he becomes in the book. His wife has never been seen onscreen, so I doubt he will murder her, which is unfortunate as I would really have liked to have seen that put on film.

Maximilien Morrel was introduced in this episode along with Jacopo, and the redemption of Morrel's shipping company is largely the same as the book.

Unknown if they will show the scene in Rome where the Count rescues Franz and Albert, but if so, that will be the next episode. (I suspect Franz will need to be introduced since in the scene where Noirtier is introduced, he has a large cut on his hand that is bandaged [implying he just had the duel with Franz's father]).