Five years have elapsed. Onedin is a prisoner in a settlement in South America from where he is rescued by Captain Baines, and they return to Liverpool. Macaulay, a wealthy Australian, keen to invest in the shipping trade with South Africa, does business with the Onedin's but when the bank crashes, the Onedin's lose out as their collateral is taken. Robert loses his shop and James's ships are forfeited but he manages to get them out of port before Macaulay claims them.

James Onedin returns to Liverpool, his ships laden with grain from Turkey. The sale of this will pay off the interest on the debt and start him back on the road to solvency. As further collateral, he offers the house which he bought for Letty Gaunt and Charlotte, who will now move in with him. It is a business arrangement but Letty perhaps seeks more from him.

Five ships, all carrying iron plate, have foundered - people betting on the losses, including Mr. Dunwoody, Elizabeth's clerk, who buys the company house where Robert and Sarah live, forcing them to return to live over the shop. James accepts a cargo of iron plate and discovers the ship is being sabotaged by Kirk, a sailor in the pay of Macauley, who also sunk the other five. Whilst Elizabeth's son, William is only interested in commerce, Robert's boy, Samuel, is keen to go to sea. James returns to Liverpool and finds that Letty, tired of waiting for a marriage proposal, has gone.

Having exposed Macauley's insurance scam James proposes to Letty, who accepts. Daniel also returns to Liverpool, now a very wealthy man. Robert considers opening a department store and travels with Captain Baines and Samuel to New York, where he is robbed and very nearly press-ganged. James takes on a voyage to import some sheep but it causes him to postpone the wedding and Letty, as a consequence, declares the engagement and wedding off.

On the eve of his voyage to Montevideo Letty tells James she will marry him - in her own good time. She also gives William financial backing for his engineering schemes. Samuel meanwhile stows away on James's ship and, when caught, James sees that he is harshly treated to put him off sea-faring but the boy will not be deterred and travels on to South America, where James makes a profitable deal.

Letty tells James she invested in William's steam engine project and he buys a flour mill in her name, sailing to Pennsylvania to buy loose grain from an ex-Cavalry officer who drives a hard bargain. James gets what he wants after a drinking bout but the grain, known as dead man's cargo, starts to shift when the ship hits a storm and needs to be moved else the ship could capsize. A man dies in the process. Daniel and Elizabeth rekindle their old flame but their decision to tell William his true parentage proves to be unwise.

William makes his peace with his parents but assures them that his interest in developing steam engines supersedes his desire to inherit the shipyard. James's failure to listen to William results in the engine blowing on the ship he is using to take Polish emigrants to New York and he puts in to Liverpool for repairs. Maritsa, one of the emigrants ,is a talented lace-maker, and Robert wants to employ her in his sweat-shop but a sympathetic Samuel advises her she would be better off going on to New York. Unfortunately another accident with the steam engine leads to the ship lurching violently, trapping Maritsa's fingers in a door and requiring two to be amputated.

James and Captain Baines sail to Palermo to pick up emigrants for America. Whilst James is ashore with his Sicilian agent Benito, several Mafia bandits led by local don Ranocci take over the ship and in the subsequent gun-battle the mate is killed and Captain Baines and the crew taken hostage. They will be released if James gives Ranocci the money taken from the locals for their voyage but James has other ideas and leads the oppressed Sicilians against the Mafia. At home Letty goes into business and William is as disapproving of his parents' relationship as they are of his intense friendship with Charlotte.

James is importing jute from Scotland and is not happy to learn that Letty's mill-workers are repairing old jute sacks, which, given that she believes in a fair wage, is under-cutting him. They argue and she is injured but, to make atonement, he takes her on his next voyage. Daniel impresses with his generosity by buying Sarah a venue for a seaman's mission but he and Elizabeth are united in their desire to stop William seeing Charlotte. They plan to send him to London but he calls their bluff.

James and Letty are to be married on board ship by Captain Baines but this nearly does not happen when a group of shanghaied sailors attempt to overwhelm them, the plan being foiled by elderly Captain Jack and the marriage does go ahead. Daniel Fogarty has returned from Australia a rich man. He has begun a charity, the Albert Fund, and is knighted for his services. He marries Elizabeth at last but James's experience has prevented him from being their best man.

Fearing unrest in South Africa Daniel asks James to bring home a large amount of gold from the country - unofficially. James naturally wants his cut. Tim, a young crew member, is subjected to a crossing the line ritual during which a man falls overboard and drowns. A cargo of wool on the ship catches fire, after which it is discovered that the gold has been stolen. Tim is responsible and speaks up to Onedin about inequality. In Liverpool Robert's son Samuel returns home whilst Elizabeth's son William declares his intention to be the richest man in the port in five years' time.

William takes a Frazer ship out in fog and gets it in a collision with one of the Onedin ships. It is arranged that the elderly, weak Captain Oliphant should be held responsible. Oliphant later kills himself and William is filled with remorse. Elizabeth is relieved to see that he possesses some humanity. However he is seeing Charlotte, supposedly the fiancée of a dissatisfied Samuel, who wants a more active life than working in the family shop. At dinner Samuel's father Robert chokes on a bone and dies.

Samuel does not let sentiment cloud his father's death, proposing to Letty that her mill-workers make bed linen which he will sell through a catalogue for his store, though Letty drives a harder bargain than he had imagined. William is shocked to learn that the 'Indian Queen', a Frazer ship which he chartered to a Mr. Lillie without his parents knowing, was deliberately sunk ,with loss of life ,for the insurance money. James has his suspicions but, even with the use of a diver, cannot proved that the cargo was never loaded.

Daniel is anxious to break the Liverpool to Manchester railway's transport monopoly of the Merseyside docks and rail board. Elizabeth suggests that they use the canal system to beat the railways. Daniel is initially unresponsive but sees the prospect of steamers being used on the canals. Samuel continues to develop his idea of mail order trading. James accepts a cargo with no questions asked or papers only to find it is from the proceeds of a robbery in Manchester.

James and Sir Daniel combine to thwart William in his bid to buy the five ships belonging to elderly Captain Murchieson on behalf of devious banker Josiah Beaumont, whom Elizabeth sees as a bad influence on her son. William moves into his own flat, where he secretly sees Charlotte, though Letty finds out. Captain Baines is tricked into buying a piano to sell in Norway, but ultimately turns the situation to his own advantage.

Elizabeth clashes with Daniel over his support for the Manchester Ship Canal, which she fears will weaken Liverpool as a port. Her anger is compounded when she is approached for patronage by charismatic young orphanage director Marcus Simmons, who tells her that families are being evicted to clear the land for the canal's construction. Daniel is innocent of this fact but it enables him to expose a business partner immorally buying up land to sell at a profit to the constructors and he supports the orphanage. James travels to Africa with missionaries as passengers, Reverend Webster and his daughter Hannah, relatives of Anne, his late wife. Hannah's religious zeal, however, proves to be a liability whilst Letty has still not told James her news.

Letty tells James that she is pregnant and Charlotte gives William the same news. He is stunned and, as he does not love her, refuses to marry her - although she has confided in Samuel that she believes they will wed. Samuel takes the news badly and, when he and James, sailing to Ireland, come across a deserted steamer full of high explosives, feels sufficiently reckless to help James put the cargo overboard, though they are successful and claim the salvage rights. William turns twenty-one and inherits his mother's share of the Frazer yard, which he intends to sell.

James learns of Charlotte's situation but refuses permission for her to marry William, whom he regards as worthless, and sends her out of Liverpool to have her child. He also encourages Daniel to stand against the greedy Beaumont as a councillor to thwart the banker's aim to take more land for himself if elected though Elizabeth is still unhappy about her husband's support for the ship canal. Captain Baines brings home a ship from South America, whose dying captain is an old enemy of his. Baines falls for the man's wife and considers buying the ship when her husband dies but James beats him to it.

As the council election approaches, Elizabeth, equally disapproving of her husband's interest in the Manchester Ship Canal and his rival Beaumont's plan to enrich himself with his 'new' Liverpool, ensures that each hears of, and publicizes, the other's plan so that both lose the election to her candidate, Marcus Simmons. Daniel then announces that he will be standing as a Manchester M.P. James, stuck in Ireland thanks to port inspectors with vested interests, finally returns to Liverpool for the birth of his son, though the child is weak and is not expected to survive.

Newly elected to Parliament Daniel joins with Elizabeth to prevent William from selling the Frazer Line to an apparent consortium, actually a front for Beaumont. To take his mind off his son's death James sails to Africa with Captain Baines to find diamonds but they end up adrift in an open boat for three months. Letty never doubts that he will come back and, on his return, he gives half of the Onedin Line to Samuel, who has married Charlotte just in time for the birth of her son.

Newly elected to Parliament Daniel joins with Elizabeth to prevent William from selling the Frazer Line to an apparent consortium, actually a front for Beaumont. To take his mind off his son's death James sails to Africa with Captain Baines to find diamonds but they end up adrift in an open boat for three months. Letty never doubts that he will come back and, on his return, he gives half of the Onedin Line to Samuel, who has married Charlotte just in time for the birth of her son.

Leaving Letty feeling adrift in their new, large country house James sails to Belfast, persuading cash-strapped Captain Seth Burgess to cut him into his steamship line. William returns from two years abroad and instantly detects the cool atmosphere between his parents. Samuel and Charlotte make it clear to him that they want nothing to do with him but feel remorseful after William dies, saving a group of children from being trampled by a runaway horse and cart. His death also goes some way to reconciling his parents.

William's death causes a rift between Charlotte and Samuel, not helped when they learn that William left his son twenty thousand pounds. Seth Burgess is duped by the infamous tavern-keeper Paddy West into paying him for a crew to sail to New York with James. However they are not seamen but largely European immigrants, including a Count and his pregnant wife. James is reluctant to put them ashore on Ellis island but changes his mind after the count saves him from an attack by a fugitive murderer. Captain Baines recovers the money from West by arm -wrestling him.

Whilst Charlotte becomes bored with life with Samuel, James learns that Elizabeth is sailing to South Africa with a mysterious and dangerous cargo. She is in fact gun-running. James needs money for the repair of his steamer and sails after his sister, illegally using a bogus distress flag to get her to stop. He persuades her that she is in an awkward position and buys the guns from her as a job lot. However, when he tries to sell them to Major Nesbitt in South Africa, he makes a heavy loss, which amuses Captain Baines.

James takes Mr. Da Silva and his cargo of lemons to the Azores but crew members Harris and McDade bully cabin boy Tom into helping them rob his possessions and kill the bosun when he tries to stop them. Eventually Tom does the decent thing, leading to their arrest. Samuel gives Charlotte three thousand pounds but, charmed by Seth Burgess, she gives it to him supposedly as a business investment. However he intends to buy back his ship 'The Black pearl' with it and leave her behind.