It's make or break time at the Hebridean family run tweed mill, 'Muileann Mhicsuain'. Time is running out for mill owner Seumas as he tries to save his business, but his corner-cutting leads to horrific consequences. A dreadful accident takes place on the mill floor that endangers the life of a beloved employee, Old Mary. With the family business in jeopardy, Seumas makes a secret phone call asking for help, but who is he reaching out to and why does he have to keep it secret from his family?

The arrival of potential Norwegian investor Johan throws a cat among the pigeons as age old family secrets and resentments come to the fore. The MacSween clan soon begin to realise that the mill is in worse shape than they thought and Seumas makes a surprise announcement to save the mill.

After years of unhappiness, mill worker Mairead finally walks out of her decade's long marriage and into the arms of the person she loves - hotel owner Cairistiona. However, as the women agree to wait for the right time to tell Mairead's husband Boyd they are together, little do they know there's someone watching from the shadows.

The community gathers for a fundraiser ceilidh for Old Mary who is recovering from her mill accident. A drunken Boyd confronts Mairead and Cairistiona in front of everyone at the ceilidh. Things turn sour between Johan and Murdina resulting in a mysterious fire starting at the hotel, trapping Murdina and Boyd inside. Will they make it out alive?

Murdina is thrown into turmoil when she realises that Johan is becoming a majority shareholder in the mill. Mill manager Sìleas offers newcomer Rory a job as one of the drivers. But just who exactly is this mysterious Irish stranger, Rory? Ivor and Dòmhnall's relationship is put to the test when Ivor shares his fears that he may be responsible for the fire.

Murdina confronts Johan with CCTV evidence of the hotel fire. Sìleas hatches a plan to save the mill, while Seumas make a sacrifice that could leave him with nothing. Still reeling from the aftermath of the 'Reul na Mara' fire, Cairistiona makes a big decision.