Some might argue that having kids means you're less likely to be alone once you're old, but that's not necessarily true. In Fiona McFarlane's debut novel, "The Night Guest," Ruth Field is a septuagenarian and a widow who lives by herself in a house by the ocean. The mother of two grown and gone sons, Ruth gets through her monotonous days by magical thinking. "If she had dinner ready in time for the six o'clock news, both of her sons would come home for Christmas." But Ruth has bigger and more surreal things on her mind right from the first page of the book.

First, she's convinced that there's a tiger in her house. And then a mysterious woman shows up on her doorstep. Frida claims to be sent by the government to take care of her, and instead of questioning her, Ruth quickly becomes dependent on this stubborn and larger-than-life woman. She's convinced Frida is from Fiji, where Ruth grew up. Frida moves in without permission and attaches herself to the vulnerable Ruth like a bur sticks to stockings.

This is a novel about aging and loneliness; it's also about deceit and selfishness. There's an Agatha Christie vibe right from the start. McFarlane excels at characters: the vocal and bossy Frida immediately comes to life on the page, while the timid and submissive Ruth is someone the reader can't help but root for. Much of the tension in the book is centered around waiting for Ruth to find her own voice and make a stand for herself, even as she questions her own memories and thoughts.

"Since Harry died, she'd rarely thought about wanting anything. Frida was the one who wanted. She wanted clean floors, a smaller waist, and differently coloured hair. Frida filled the world with her desires. And Ruth admired it. Why not be like that?"

Ruth does want some things, it turns out. She reaches out to an old love she met in Fiji; Richard comes to visit her, and one can't help but think of "Love in the Time of Cholera" as the two senior citizens consummate their relationship in their twilight years.

It's not all happiness in the house she shares with Frida. Frida has the patience of a tiger and the ulterior motives of one.

"The Night Guest" is an intellectual page-turner that examines fears and anxieties and trust. Ruth wants to fill the emptiness of her home. Yet she also wants the certainty of the uncertain that she found in the jungles of Fiji. "For some time now she had hoped that her end might be as extraordinary as her beginning."

As so many of us do.

Michele Filgate is a writer and indie bookseller in New York City.