This description by Helga Quadflieg

The episode lays out the lines of conflict along which much of the plot of the series is to develop:

James and Anne have moved into a cheap basement in order to save money to buy back Onedin Line shares; James is determined to subordinate everything to his aim of regaining control of the Onedin Line of the Onedin Line

Callon and his son are killed in a fire.

Callon’s niece Emma inherits the Callon Line and the majority of shares of the Onedin Line; by wilfully misunderstanding Fogarty’s “may I propose to ...”, Emma manoeuvres Daniel into asking her to marry her; Fogarty is designed to become the new Chairman of the Onedin Line

While James is away at sea, Emma “buys” Robert’s support for Fogarty’s election by handing over 1500 Onedin Line shares to him
To Elizabeth’s chagrin, Albert is absorbed in his work on the steamship and pays little attention to her; Fogarty continually insists on changes to Albert’s designs, thereby fuelling the rivalry between them and deepening Albert’s bitterness towards Elizabeth; Elizabeth is competing with Emma for the gentlemen’s attention.

After the end of the American Civil War, James’ hopes concentrate on profitable trade with America. Knowing Baines to be “the hardest driving mate”, he employs Baines as mate on his first voyage on the newly-chartered “Star of Bethlehem”. He (self-consciously, as often when a disclosure of feelings is involved) asks Anne to accompany him

Yet soon trouble is brewing in two quarters:
On the one hand there is Jessop, who had been seen earlier publicly speaking for support for the formation of a sailors’ union. Being known as an “agitator”, he repeatedly finds it difficult to find a job and therefore has to ask for an extension of his credit in Robert’s shop; a plea which is refused by a very condescending Sarah. On board the “Star of Bethlehem”, he tries to encourage the crew to form a “Union” in order to fight more efficiently for a general improvement of the working conditions for sailors. Although even Jessop agrees that the conditions on this ship are no worse than elsewhere, under his leadership discontent is growing on the ship.

To James’ satisfaction, Baines’ cure against this discontent is to drive the men even harder. On the other hand, Anne is increasingly worried by James’ harshness with the crew, whereas James in return feels increasingly uncomfortable about her appeals to his “conscience”. When, during a sudden manoeuvre ordered by Baines, a sailor working on the outside of the ship falls into the water and is killed by a shark, the blame for the accident is put on James and his relentless insistence on speed. In the ensuing argument, James for the first time ever cuts a discussion with Anne short with “there’s an end to it”.