A very successful series by indie novelist Shayne Parkinson
Set in 1880s New Zealand, the "Promises to Keep" series stars Amy, the youngest daughter of an isolated farming family. In order, the books are:
Sentence of Marriage
Mud and Gold
Settling the Account
A Second Chance
Amy, a very young and innocent teenager, leads a mundane, industrious but reasonably happy existence on her widowed father's farm, cooking and cleaning for her two older brothers as well as her father, Jack. Then her life is disrupted by the arrival of two colorful characters.
The first is the new wife Jack brings home from a farm-machinery-shopping visit to the bustling colonial port of Auckland. Susanne ("don't dare ever call me Susie") is a high-and-mighty would-be socialite who married Jack because at the age of 25 she was on the shelf. Naturally, she didn't expect the grim existence of a back-country farm. Amy does her best to make up for her new stepmother's laziness, but gets no thanks at all from the miserable creature, let alone appreciation.
A kind of rancorous peace is established over the next two years ... but then, when Amy is at the very vulnerable age of 15, her stepmother's elegant and charming 20-year-old brother arrives. Though it is obvious that Jimmy is eminently untrustworthy, the ignorant and innocent lass trusts him completely, with a predictably tragic result. It is a classic tale of seduction and betrayal, perhaps, but leavened by such excellent descriptions of daily life in the rural setting, and with such an unexpected outcome that the reader is compelled to carry on from one book to the next. As one amazon reviewer said, "I found myself really caring for the characters."
A canny marketer, Shayne Parkinson published the first eBook for free, hooking the reader into the story of the fortunes and misfortunes of her hard-working, well-meaning, biddable heroine. It has been a very successful ploy: according to smashwords ratings, she has sold over 50,000 books. The series is also published in print.
You can read more about Shayne Parkinson on her website. You can also read an interview HERE.