One of those performances you just lose yourself in carries off “June Again,” a sweet and sentimental portrait of dementia, and the “paradoxical lucidity” that gives some sufferers a short respite from the memories, manners, skills and knowledge that disease has stripped from them.

Veteran Australian character actress Noni Hazlehurst is a window into June Wilton, the woman she’s been for five years since a series of strokes left her with vascular dementia — her memory shot, her grasp of time, the present as opposed to the past, unstuck — and the woman she once was.

Hazlehurst, of such recent Oz films as “Ladies in Black” and “The Mule,” lets us see the lost soul June is, the pushy, outspoken bulldozing matriarch she once was and the flashes of panic that cross her face as she feels her “temporary lucidity” about to leave her, perhaps for the last time.

It’s marvelous work at the heart of a story about second chances, making amends and maybe fixing the family world that she slowly figures out has “gone to pieces” since her strokes five years before.

Writer-director JJ Winlove’s debut feature takes us into a life interrupted and the mad dash to take in all that’s happened to her two children, her grandchildren and the family business since she “went away.” While it has a familiar feel that makes this story quite predictable, Winlove trips up expectations by simply erring on the side of “Let’s be realistic,” often as not. And through it all, his star keeps us involved.

When we meet her, June is having trouble distinguishing reality from the flashbacks that come, unannounced, reminding her of relatives who have visited and a romance of long ago. She’s well-cared for at Winburn Rest Home, doted on by the staff whose names she can’t recall. Her doctor (Wayne Blair) makes little headway in even the simplest tests in his evaluations.

“Try to read this and do what it says,” he says. She can’t quite plumb what “Close your eyes” means and what she must do.

She’s pleasant enough, befuddled about forgetting her room number, the combination to the door leading into the yard. But she’s lost. Until one day she isn’t.

“Where the hell AM I?” The staff is startled, but they’ve seen it before. They scramble to get her family over here for this little patch of lucidity. June “does a runner” with the aid of a sympathetic cabbie.

“It’s like a prison in there, the decor ALONE…”

But the house she goes back to has been sold, even though she’s able to steamroll the ballerina-dressed child practicing her violin (“Debussy’s First Arabesque!” June enthuses, recognizing it.) who now lives there into giving her some of her mother’s clothes. The furniture’s long gone, even June’s treasured dresser.

And her daughter and son seem more guarded than delighted at this turn of events. Ginny (Claudia Karvan) endures her “You couldn’t wait until I was in the GROUND?” protests about the house and furnishings, and is helpless as willful June storms back into the family wallpaper business that seems to have gone to ruin. Ginny isn’t wholly forthcoming about the reasons she and her brother Devon (Stephen Curry) are no longer on speaking terms.

As the day unfolds, June learns of the tragedies and trials that her own tragedy kept her from learning about, and presses on with plans to fix things before she loses it again.

“Is there ANYthing that hasn’t fallen apart in this family?”

Winlove largely avoids “cute” in telling this story of June’s journey from oblivious to sentient, only to realize she was another form of “oblivious” back when she was ruling this clan and putting everybody in a position of wanting to please or just appease her.

“Who taught you to hug?” she wants to know of one of her obviously emotionally-stunted kids.

“YOU did!”

There are hints of “The Notebook,” “The Father,” “Still Alice” and “Still Mine” and every other movie about dementia, and even a whiff of “Awakenings” to this bittersweet “Flowers for Algernon” story of the ebb and flow of awareness.

But Winlove is content to keep his story simple and leave the film in the hands of an actress who makes June not just pitiful and sympathetic, but a real piece of work who did a number on her family long before her illness came along and broke their hearts.

Rating: unrated, some profanity

Cast: Noni Hazlehurst, Claudia Karvan, Stephen Curry, Nash Edgerton, Wayne Blair and Otis Dhanji

Credits: Scripted and directed by JJ Winlove. A Samuel Goldwyn release.

Running time: 1:39