Two girls are walking home from school, sharing secrets. One tells the other that the soul of her father, who had died a few months back, inhabits a giant fig tree in their yard.

"How big is a person's soul?" asks her friend.

In The Tree, a storm-tossed meditation on grief and loss, it is very big, indeed.

Set in the parched farmlands of Australia, and starring Charlotte Gainsbourg as the widow left with four children, Julie Bertuccelli's film is a small and lovely tangle of mystery and emotion. When Peter (Aden Young) returns home from a job - he transports houses on a huge flat bed - a shudder of pain runs up his arm, and he succumbs to a heart attack. He dies in his pickup, which has rolled into the garden and stopped beneath the gnarled and towering limbs of the tree.

In the weeks that follow, Gainsbourg's Dawn, dazed and devastated, struggles to get out of bed, to get on with her life. It isn't until her 8-year-old, Simone (a beaming and terrific Morgana Davies), creeps into the bedroom one night and tells her mother that she's been talking to her father, and that he's in the big Moreton Bay fig tree in the garden, that Dawn seems to emerge from her stupor.

At first, her daughter's imaginary discovery - it is imaginary, right? - brings a sense of peace to Dawn and her kids. But then, the tree itself seems to take on a presence, a force, literally upending the rhythms of their life.

Bertuccelli's first film, 2003's Cannes-winning Since Otar Left, similarly dealt with a family coping, or not coping, with a loved one's death. Despite the potential for some supernatural grandiosity, the tone here remains understated and quiet, and Gainsbourg's performance feels lived-in, and deep, and right.