She waits and waits, eventually sleeping beneath the undies, and leaving her mother a series of handwritten signs so she can find her.
Two unlikely saviours come to Millie's aid. Grieving widower Karl the Touch Typist is on the lam from his rest home.
And eccentrically cranky Agatha Pantha has been leading a lonely and rigid life since her husband died.
Both are octogenarians and not always fans of obeying the rules. Together they set off on an eventful and unpredictable road trip in a bid to prevent Millie's mother running away to America.
As they travel by road and rail the unlikely trio have amazing adventures. There are superheroes and bullies, a stolen car, elderly people pashing, things on fire.
For all of them this is an incredible journey.
This novel has been creating a lot of buzz, and deservedly so.
Davis takes topics we may prefer not to think about - the sadness of old age, the gradual closing down of life, the devastation of death - and plays with them, producing a story that is amusing yet at the same time tragic.
It's a clever trick, and although the action veers towards the cartoonish at times, the overall result is poignant and immensely thoughtful.
The history behind this fiction is that Perth-based Davis lost her mother very suddenly in an accident while she was travelling overseas.
Lost & Found is a distillation of her grief, the result of her discovery of the sadness that stalks us all, of the inevitability of loss.
It is also fantastically quirky and the child's eye perspective in particular is endearing and very clever.
This is a wonderful debut novel, already sold into 25 countries.
Davis captures the Australian landscape in all its breadth and grandeur. Her voice is fresh, her take original and mostly her prose is spare and useful.
If she lapses into cutesiness everyone once in a while I'm very happy to forgive her.