Soon after her father’s death, a seven-year-old Australian girl in bright red gumboots is abandoned by her mother in the big ladies’ underwear section of a department store. With the aid of two lately acquired octogenarian friends, she’ll set out cross-country to find her.

This quirky matchup makes for a multifaceted meditation on loss and grieving in Brooke Davis’ bighearted debut, Lost & Found. The novel, available stateside today, is already an international bestseller.

“It’s been the biggest surprise,” says Davis, who lives and works as a bookseller in Perth. “It just sort of was this weird little book, but it’s done really well in Australia, and it keeps doing well. I thought my dad would read it, and that would be about it. To get published is a huge deal, but to actually get your book read by a lot of people—it just doesn’t happen that often.”

The biggest surprise of Lost & Found is how funny and tender its solemn subject can be. Death palls the lives of three main characters, who cope in strongly divergent ways: Millie Bird, 7, is a buoyant, intrepid young girl who matter-of-factly catalogs deaths (people, animals, insects, etc.) in her “Book of Dead Things.” She meets Karl the Touch Typist, 87, in the shopping mall food court. He’s a widower who wistfully remembers life with his wife.

“He dreamed of her, of course he did, and woke up thinking, That is the only time I’ll see her now. He stood up in the darkness and leaned into her clothes, with his arms out like he was flying. Her clothes were so cold,” Davis writes.

Karl helps Millie make it home, but her mother’s still missing. The Birds’ neighbor, Agatha Pantha, 82, sees Millie through the window, but hesitates to get involved. She’s not been out of the house for years, since the thoughtlessness following her husband’s death.

“They talked with their face only centimeters away from hers. I understand, they all said, because Susie/Fido/Henry died last year/last week/ten years ago because she/it/he had lung cancer/was hit by a car/wasn’t really dead but was dead to her because he was living with a twenty-six-year-old on the Gold Coast,” she writes.

Lost & Found was written as part of a dissertation at Curtin University, where Davis earned a PhD in creative writing. It was spurred by a personal tragedy: In 2007, her mother died in an accident while Davis was traveling through Southeast Asia. She found out from her father, by phone, and swiftly returned home.

“When my own mum died, I spent quite a bit of time just walking around cemeteries,” Davis says. “I would just stare at those dashes [between birth and death dates], and I couldn’t quite believe that was the whole person’s life on that gravestone. I thought about my mum’s life and all the people I love—how you could just reduce it to that lin e between a start and an end date? It seemed really unfair, because when the person you love dies, you want everyone to be mourning them. The world of yours has forever changed, and you can’t believe that everyone else isn’t feeling the same.”

Davis endows Millie with the sentiment. “Millie ran her fingers over the line in between the question mark and Spider’s death-year. Back and forth, back and forth. It was strange, she thought, that this line—this long, straight line—was all there was to show of his whole life,” she writes.

Lost & Found reminds us that the measure of a life is much more than a dash on a stone. In sharing their grief for love lost with one another, Millie, Karl and Agatha become intimates, building a constellation of sincere support.

It’s a phenomenon Davis has experienced by including an autobiographical article titled “Relearning the World” at the book’s end.

“Whenever I go and do events, it makes people feel like they can share their stories with me, because they know mine. If you allow yourself to be vulnerable in front of other people, it breaks down borders between you, and you can just be humans together,” she says. “I’m really appreciative of that now, that I can have quite intimate conversations with strangers about these really difficult things. I feel really privileged for that, and I don’t think that would have happened if that piece wasn’t included at the back of the book.”

Megan Labrise is a freelance writer and columnist based in New York. Follow her on Twitter.