The date of construction of the manor house is uncertain, however the estate's chapel dates back centuries, to a time when the viscounts of the area were Catholic.
In 1756, Jamie Fraser begins his parole at Helwater, where he works as a groom for Lord Dunsany and the estate. While there, Dunsany's elder daughter, Geneva, blackmails Jamie into taking her virginity just before her marriage to a much older man. Their one-night stand results in a son, and Geneva's death by hemorrhaging after the birth.
After Jamie shoots the elderly Earl of Ellesmere to save his newborn son William, Lady Dunsany offers to ask Lord John Grey to use his influence to secure Jamie's release; however, Jamie cannot bear to be parted forever from his son just yet, and he decides to stay.
As William grows older, he begins to resemble Jamie more and more – not just in his slightly slanted blue eyes, but in the cock of his head and the set of his shoulders – and although no one has yet made the leap that William could be the groom's son, they remark about the resemblance. In 1764, Jamie talks to Lady Dunsany about her standing offer, and he secures his pardon through Lord John. Before he leaves, John tells him that he will marry Isobel Dunsany, Geneva's younger sister who has been like a mother to William, and that he, John, will become William's stepfather and legal guardian.
Lord John visits Helwater to attend Geneva Dunsany's funeral. During one sleepless night, he wanders into the chapel and stumbles over Jamie, who had been lying prostrate on the cold stone floor in an act of penance, though John doesn't immediately realize that is what he was doing.
During another brief visit, John asks Jamie if, during his time as a Jacobite rebel, he had ever heard the name Gerard Grey in connection with the cause. Jamie had not, and John gives him permission to write letters to anyone he chooses, in order to discover any connection between the Greys and the Jacobites.
Months later, John visits again to inquire whether any of Jamie's letters had borne any responses of interest, regarding his father and the Jacobites. He also seeks Jamie's advice about his stepbrother, Percy Wainwright. When Jamie realizes that Percy, arrested for the crime of sodomy, was also John's lover, their encounter escalates to disgust and anger respectively, and culminates in Jamie throwing a punch at John's head that narrowly misses; had he met his mark, John is almost certain the blow would have killed him. John also comes to the horrifying realization that his callous remark about making Jamie submit to him sexually had provoked not just disgust in Jamie, but fear, suggesting that Jamie had already experienced the sexual violence that John had implied. He does not speak to Jamie again before he leaves Helwater, though Jamie does leave him a cryptic note: "I believe your lordship to be in pursuit of a wild goose."
In spring of 1760, Jamie encounters Tobias Quinn, an old acquaintance from the days of the Rising. Soon afterwards, Jamie is summoned from Helwater to London, where Harold Grey, Duke of Pardloe intends to employ the Scot's knowledge of the Gaelic language to translate a poem in connection with an investigation. Not knowing the duke's intended purpose when the soldiers arrive to take him away, Jamie fears he may never return – may never see his son again.
He does return, however, after a long and harrowing journey through Ireland in pursuit of a possible Jacobite traitor. While accompanying Lady Dunsany and Lady Isobel – as well as their guest, Mr. Wilberforce, and William – on an outing on the fells, a fog comes down just as William has gone missing. Terrified but persistent, Jamie finds the little boy, and realizes in that moment that he truly loves William.
Before Lord John departs once more for London, he and Jamie resume their odd half-friendship by engaging briefly in a spoken game of chess.
- Gosford House stands in for Helwater in Season Three of the Outlander television series.
- While Helwater is fictional, there is a mountain in the Lake District called Helvellyn, as well as a stream called Helvellyn Gill. In Voyager, Lord John Grey and Jamie travel over Helvellyn Bridge and past a tarn before arriving at Helwater.
- Lord Dunsany kept a number of horses during the years that Alex MacKenzie was a groom there.
- Bess, one of the drayhorses.
- Blossom, one of the drayhorses.
- Mille Fleurs, also known as Milly and Millyflower; a skittish bay mare. This is the horse William spooks when he throws his tantrum on learning that Mac the groom is leaving.
- Bella, an older mare.
- Deacon, also known as "Deke"; an older gelding.
- Philemon, also known as "Phil"; an eight-year-old dark bay.
- Two of the mules employed on the farm are named Whitey and Mike.