This is her last novel, a standalone -- stronger plot than many of them, she tends toward the rambling incidents.
Jane lives with her mother and her aunt at her grandmother's, where she is squelched and miserable. Her mother really can't stand up to the grandmother, who is obsessively jealous of her mother's love, and Jane's only friend is the wretchedly treated girl who works next door as a servant, which her grandmother allows so she can sneer at Jane's taste for low company.
But then Jane learns that her mother is not, after all, a widow. And one day, there is a letter from her father, saying that Jane should come live with him for the summer. Jane hates it, but is not asked, and her uncle observes that he is probably doing this only to annoy them, so they should pack Jane off, and once he realizes they are not annoyed, he will stop.
So Jane is packed off to Prince Edward Island -- and finds that she loves it.
It proceeds through her life at PEI during the summers, her life back in Toronto when she has to return, discoveries about her parents and why they separated, and clashes with her grandmother before the grand conclusion.