It's a melodramatic romance, set mostly around the village of Brightdale, telling of the loves of Ethel Arden, nicknamed "Brightie" by her family. A 19-year-old orphan, she was rescued from a shipwreck as a baby, and brought up by her indulgent foster-parents, the elderly Ardens.
Ethel has a gently flirtatious friendship with Will Brackenbury, a nice-but-irresponsible miller's son, which goes sour when he asks to marry her and she replies that she could only marry a man in uniform. In response partly to this, and partly to his father's criticism for high jinks including suspending an old farmer from a tree while scrumping apples, Will quits town and joins the army incognito.
Ethel is hurt, but not much, and aims her sights loosely at Cecil Wymmering, whose family owns the nearby Wymmering Manor; but she snubs him at a party when she meets the world-weary Major Leslie Tempest, 15 years her senior. The two develop a strong mutual attraction - despite, unknown to Ethel, Tempest's intended engagement to a society heiress - and after a picnic, they agree to meet the next day in a clifftop dell. Ethel goes home to find a mysterious visitor called Mr Richards, evidently known and disliked by her foster-parents, who gives her a gift of a gold bracelet.
The next day Ethel goes to the dell, but Tempest doesn't turn up (the "broken tryst" of the title). Unknown to her, the previous night Tempest had a near-fatal fight with the stranger, and both have left town. It's later explained that the two are enemies over an earlier disagreement over gambling. Tempest sends a short and formal note of apology for breaking their appointment. Ethel is deeply upset, and has no backup (Cecil is engaged to someone else). She throws herself into study, and time passes. She nearly dies of a fever, and on her recovery goes to stay with London relatives of the Ardens, touring Europe with them, and starting to enjoy life again.
Meanwhile, Will Brackenbury has returned to Brightdale, having earned an honourable discharge for saving his colonel, Lord Lyndon, in battle. After initial resistance, his father and he make their peace. At the time of his arrival, a man has been found dead after an accidental fall near Brightdale; it is "Mr Richards", revealed to be Richard Arden, the elderly Ardens' son and Ethel's dissolute father. His earlier visit to the Ardens had been to claim Ethel as his daughter, a scheme he only gave up when the Ardens gave him their money saved as Ethel's inheritance. Will is sent to London to fetch Ethel home for the funeral.
Will finds Ethel at a vulnerable point, just shaken by seeing Major Tempest with another woman at a concert, but she comes home with Will; both are favourably impressed by the other's new-found maturity. Ethel arrives just in time for Richard Arden's funeral, and Will explains to her the family history; she is upset, but delighted to find that she is her foster-parents' grandchild. Over time, Ethel and Will become closer, and the two marry, though with considerable misgivings on her part because she's still thinking of Tempest.
After their first child is born, Will's old commanding officer, Lord Lyndon, comes to visit Brightdale to thank the young soldier who saved his life. Ethel is horrified to find that Lord Lyndon is Leslie Tempest (Will knows about Tempest, but not that his commanding officer was the same person). Tempest has come to ask Ethel to marry him, but he does the decent thing and takes his leave. Ethel's upset after he has gone, however, gives all away, and the incident drives a further wedge between between Will and Ethel.
On rather frosty terms, they continue for a few years, Will becoming a gentleman farmer and acquiring a manor house in idyllic surroundings, until finally they see a newspaper story telling that Tempest has died in action. Ethel is finally able to cry and release her pent-up disappointments, and the two are reconciled to live happily ever after.
Location / chronology questions
I found The Broken Tryst very readable; as a single-volume novel, it tells the story quite tersely, and it's virtually free of the highly purple landscape/sunset descriptions of MG's later novels. It's not explicitly set in the Isle of Wight, but as I wrote earlier - see Brightdale - an added interest is that its location there is highly identifiable. Brightdale is Brighstone; the route over the down to Wymmering Hall locates it as Westover Manor, Calbourne (though the architectural details differ from the reality); and the landscape description of the manor where Will and Ethel finally make their home matches Mottistone Manor.
Despite the whole family complications and interlocking past history being a bit contrived, the book worked for me. However, I did get distracted by needing to Google frequent puzzles about fixtures and dates, and I agree partially with the Belfast News-Letter reviewer's comment at the time:
As for the author's chronology, all we can say is that it baffles us completely. We should like it to be explained to us what Spanish sea fight is recollected by the lieutenant, and also in what Eastern campaign young Brackenbury gains two medals and a clasp.Actually the chronology is reasonably consistent. The general setting appears to be late 1860s: Ethel's visit to St James's Hall to hear "Nilsson" sing must refer to Christina Nilsson, and most likely to a celebrated concert in 1869 marking the move of the Philharmonic Society to that venue. Tempest's having a "pile of photographs" places it after after affordable paper prints came in (see Google Books) and Lieutenant Arden's prized roses, the Marshal Niel and Cloth of Gold, would have been fairly new varieties (this 1913 Biltmore Rose Catalogue dates the Marechal Niel's introduction to 1864). As to Will's "Eastern campaign", the timeline would fit the 1868 Expedition to Abyssinia, which was launched from India.
None of this fits Lieutenant Arden's rant about an English sea-battle "exactly this day twenty years by my log-book" with "a Spanish squadron" - unless he means that he was 20 years old. There are a few such naval engagements in the 1796-1808 Anglo-Spanish War, and the timeline would work if we assume him to be in his mid-80s. On the other hand, some of the specifics are plain authorial invention: the "late affray with the Neilghoorkees, at Bombadore", in which Tempest dies, is fictitious, and I'd bet money it was inspired by the title of Major William Murray's 1834 An account of the Neilgherries, or, Blue mountains of Coimbatore, in Southern India.