A Crack in the Line - Michael Lawrence

Alaric lives with his father at Withern Rise, a remote English country house. Since the death of his mother after a horrendous train crash it's just been the two of them - the house, and their relationship, are slowly falling to pieces. One snowy day while his father's away on business and his interfering but well meaning aunt is trying to restore order, Alaric ventures into a forgotten part of the Victorian mansion and rediscovers a miniature of Withern Rise his mother made. When he touches it he feels searing pain, and when he opens his eyes Alaric is in a cleaner version of home, with a strange girl who seems to think he's the intruder.
Naia tries not to think about the terrible time when she and her father didn't know if her mother would survive the injuries from a devastating train crash two years ago - the doctors said it was fifty/fifty, and the odds were on their side. Alone one snowy day she's shocked to discover a strange boy in her living room, a boy who seems to think she's in his house rather than the other way around.
The first in a trilogy, A Crack in the Line explores the idea of parallel universes - Alaric and Naia are similar in almost every respect, except gender, and their lives continued on near-parallel tracks until the accident two years earlier. Alaric and Naia are somehow able to cross into each other's lives through the model of Withern Rise that was carved from the wood of a massive tree on the property. For Alaric, the sight of his mother restored to life is a painful joy.
I was unprepared for A Crack in the Line to so completely end on a cliffhanger - although I knew it was a trilogy going in, I had expected something of a full narrative with ends to be tied up later. There is, however, no resolution of any aspect of the plot, and I found this so profoundly irritating that it has coloured my perception of the novel as a whole, so that I cannot appreciate the awe it's inspired in others - unlike Sarah Meador I certainly haven't spent the intervening time since reading it "in a stupor, scared and searching for one of the alternate realities lying on the grounds of the Victorian mansion in the title."
I will, however, borrow the rest of the series from the library; I hope that the knowledge that I can read it as though all three volumes comprise a single text will allow me to better appreciate the complexity and thoughtful fears that Meador detected. - Alex