Walter's death has changed the whole picture. Malcontent breeds amongst workers, especially at the shipyard. Larkin has been forced to leave the city. Andrea, to Sofia's embarrassment, is staying at her house. The Chairman, Lord Pirrie, is shocked, and fights with his former friend Henry Carlton – Kitty's father – whom he holds responsible. He seeks an understanding with Michael MacCann, one of the leaders of the workers' movement. They are both intelligent and moral men. Mark keeps his mind on his job and finally identifies the problem with the steel: impurities. But the steel complies with regulations. Eventually Thomas Andrews will see his point, and a new relationship will form. But work is not Mark's only occupation: he finally kisses Sofia. As he goes back to his father, he is assaulted by Bernard Doyle. He accuses him of having left behind his fiancée, Bernard's daughter Siobhan, who died at childbirth.

Mark's story is fully revealed. When he lived in Belfast, he had a girlfriend, Siobhan Doyle. She was supposed to follow him but never did. Siobhan died soon after. His father told him she had died of TB. Instead, she had died at childbirth without him ever knowing. Mark realises how much Siobhan suffered, and is heartbroken. She was sent to a convent. To his utter shock, he finds out that the child survived: a baby girl. He tries to find her, but the nuns will not tell him anything. An accident occurs that forces him back to work: RMS Olympic, a ship in the same class as Titanic, has had a serious accident. Mark is asked to study the implications. Mark's new discoveries are now less important that delivering on schedule. Pirrie and Andrews discover that Mark Muir is a Catholic, but guard his secret.

Losing his job is not Mark's only problem. Sofia knows his truth. Mark tells her everything. Even about Siobhan and the baby. She eventually forgives him. It is also time for Mark to reconcile with Sean. Mark's situation seems to get better still when JP. Morgan arrives. When told the reason why his chief metallurgist has been fired, Morgan has him immediately reinstated. Mark starts looking for a viable alternative to the double hull, an alternative he finds in higher bulkheads. General Elections are in sight. Home Rule for Ireland is at stake. The possibility that London putting a stop controlling the island is strongly opposed by the Protestant minority, which fears the power the Catholic majority would get. Emily persuades her brother Michael to stand for Parliament, and Pirrie helps and supports his main counterpart in the shipyard.

The high staked General Elections are drawing closer. The magnates have their own candidate, the Unionist extremist Albert Hatton. The fact that Pirrie does not support Hatton makes him an enemy of the ruling class. Michael is campaigning for Labour. His sister Emily helps him. But she gets arrested for giving out leaflets. This is a political measure, and Emily is only the scapegoat. On the ship front, Mark's proposition to erect higher bulkheads to defend Titanic is crushed by Ismay, the Chairman of White Star Lines, the company Titanic is being built for. When the elections occur, Albert Hatton wins a handsome majority. The third candidate, Michael, only gets a very small number of votes. Protestant and anti Home Rule extremists fume with rage and hatred, and Michael is assaulted, cruelly beaten and forced from Belfast. His brother Conor has become a terrorist and has taken lives.

The Admiralty has opened an inquiry into the Olympic accident, and Pirrie, Andrews, Morgan and Mark are invited to London. Mark is pleased to see his old friend Kitty, who has become a star. At the inquiry, the First Lord of the Admiralty, Winston Churchill, suggests that the yard could serve several ends in case of military escalation. Joanna Yaeger, Mark's old friend from New York, and Morgan's protégée, is forced into a very dangerous position: a spy. With her unparalleled access she can prove to be extremely useful to the Austro Hungarian and German causes. Back in Belfast, Mark faces a new crisis. Andrea, Sofia's old fiancée, has seen her with him and has told Pietro. Sofia is forced to choose. Sofia stays Mark. Finally he agrees to follow Sofia: they will move to London, together. He will leave Harland & Wolff and all hopes to ever find his own daughter. In a breathtaking ceremony, the Titanic is finally launched.