Dr. Mark Muir, a young American metallurgist, persuades American tycoon JP Morgan to hire him for the biggest shipping project the world has ever seen: RMS Titanic, at the Harland & Wolff shipyard, in Belfast. The shipyard's visionary Chairman takes the young scientist under his wing, introducing him to Belfast's Protestant elite. Mark quickly catches the eye of the charming, albeit spoilt, daughter of a magnate: Kitty Carlton. But he is also intrigued by a very different woman; Sofia Silvestri, an immigrant's daughter. Belfast, seen through Mark's eyes, is a city ridden with divisions of class and religion, from which, as a stranger, Mark should be far removed. But we soon discover that Mark is a man with a past mysteriously connected to the Catholic suburbs of Belfast.

Dr. Mark Muir's real name is Marcas Malone, and he is the son of a Belfast Catholic dockworker, Sean. Sean is an old drunkard, broken by a life of unimaginable harshness. His only remaining pride lies in Mark. Now, Sean is worried that if Mark's identity were to be disclosed, he would lose his job at the Protestant - managed shipyard. But Mark is careful and guarded. He starts finding out things about the steel used that lead him into conflict with chief designer Thomas Andrews. In the meantime, social tension escalates. A prominent figure in the labor movement, Jim Larkin, is organizing the workers in Belfast. While Kitty Carlton seduces Mark with her elegant charms, Sofia gets more involved in her fight for freedom, which she interprets in a personal way, turning down her father's apprentice, Andrea Valle, much to her father's grief.

An accountant from the United States, Samuel, makes Mark feel jealous. Samuel is handsome and witty. He is American and unaware and uninterested in divisions. For Sofia, he represents a real temptation: Pietro is better and Mark still can't leave his job. Mark is still uncertain: he still hopes to find his daughter. Mark discovers what the girl's name was: Sarah. The girl might live in a small village outside Belfast. But the girl, who had indeed been living there, has left. They have moved to Belfast but no one knows where. Andrews fights, and looses, a memorable battle to equip Titanic more life boats. And while Pirrie and Churchill try to campaign for Home Rule in Belfast, the divide between the Catholic and Protestant communities has grown. Lord Pirrie, by now disillusioned with most of his liberal principles, falls ill.

The time has come for the great ship to leave for the New World. As Morgan always wanted, Titanic's maiden's voyage will become one of the first great PR events. Sofia and Joanna Yaeger are friends and she gets her a job as an illustrator for the New York Times. Pietro uses most of his money to buy her a ticket. Mark himself only gets on board by chance. The group also includes Jack Lowry, a young riveter we met since the beginning of the story. Violetta with the baby, whom Michael MacCann, has come back to marry. Joanna will be onboard – and so will Kitty, by now an acclaimed actress. A little girl by the name of Sarah, with her mother, will board Third Class. Neither Mark nor his daughter are aware of their presence onboard the Titanic. And, while the ship sails for New York, and Mark and Sofia finally find happiness and reconciliation, we are left asking ourselves: who amongst our characters will survive the great disaster?