Lurking in dark territory

“Trespass’’ opens like a thriller. A 10-year-old girl named Melodie, herself an unhappy migrant from Paris to the Cevennes, sets aside her ham sandwich with its “repulsive grey-green shimmer” and walks away from her school picnic in search of solitude. She finds it on the bank of a stream, but before she can dive into the deep pool she sees something that starts her screaming. Only much later does the reader learn what it was.

The next two sections take us in turn to a deserted antiques shop in London, where Anthony Verey, the 64-year-old owner, sits drinking coffee, and to a forest in the Cevennes, where Audrun Lunel, the owner of the forest, also 64, is going for a walk. In the hands of a lesser writer, these mysterious jumps might be an irksome strategy, but Tremain’s prose is so immediate and her sense of character so compelling that I was happy to follow her into the lives of her five main characters and their complicated pasts even when I had no idea how they connected.

The story of “Trespass’’ is propelled by Anthony’s decision to close his once fashionable shop and begin his life over in the south of France, where his sister, the only person for whom he feels anything like true affection, has made her home. “Veronica lived with her friend Kitty in a fine old stone farmhouse, ‘Les Glaniques’, in one of those villages south of Anduze, in the Gard, where the 21st century hardly seemed to have arrived and where Veronica went about her life in a mood of robust contentment. She was getting fat . . . but she didn’t mind and Kitty didn’t mind. They went together to the market at Anduze and bought bigger clothes.” The plain and practical Kitty paints watercolors that she is hoping will illustrate the book that Veronica, a landscape gardener, is writing: “Gardening Without Rain.’’ But Anthony’s arrival quickly brings an end to their contentment. While Veronica adores her little brother, Kitty rightly fears him — and his effect on her friend.