The new Australian movie “Little Fish” is a “Lord of the Rings” elf reunion, starring Cate Blanchett and Hugo Weaving, who played Elrond and Galadriel in the blockbuster trilogy. But here their characters aren’t ancient elves with sparkling eyes; they’re just junkies with bad credit. Produced by Mel Gibson’s Icon Entertainment and starring Ms. Blanchett, Mr. Weaving, and Sam Neill, “Little Fish” is about lower-class losers getting off the junk and staying straight. Although most of us avoid junkies in real life, actors are irresistibly drawn to them, and so “Little Fish” is an actor’s project but – in an unlikely twist – a worthwhile effort. Instead of the long takes and affected naturalism of most actor’s movies, this flick is shattered into a million shards of multicolored pop imagery, doling out background in such a miserly manner that you find yourself eagerly scouring the screen for clues about these characters.

Tracy (Cate Blanchett) was a junkie and a criminal until she got clean and became a video store clerk. Now she’s trying to expand the store with her boss, but doesn’t have the heart to tell him – or her ex-junkie mom – that her history of credit card fraud has torpedoed her loan application.

Desperate for money, she turns to her dealer brother Ray (Martin Henderson),who’s cooked up a harebrained criminal scheme with Johnny, her ex-boyfriend and former shooting partner, who just came back from Vancouver and may or may not be using again. As if that isn’t complicated enough,Tracy’s father figure is Lionel (Mr. Weaving), a junkie and one-time rugby great whose boyfriend is the local crime lord (Mr. Neill). Untangling the relationships – who slept with whom, who shot up when, why everyone’s so mad at Johnny all the time – is almost too complicated, but it’s a rare movie that makes you want to know more, not less, about its characters.

Ms. Blanchett is such a striking screen presence that she often gets away with little more than posing and unleashing flawless accents, but she attacks her role here the way a starving man goes after a pork chop. Mr. Neill is all walled away behind a role that feels like it could be unpeeled for hours: a sadistic, gay crime lord who’s simultaneously retiring and leaving his wife. But it’s the beautiful losers who steal the show. Dustin Nguyen’s Johnny is the high school golden boy, all grown up with the realization that his best years are behind him – an apology for his latest mess eternally on his lips. And Mr. Weaving’s Lionel is practically a monument to pathetic grandeur. It’s impossible to look at him without feeling your skin crawl in all directions at once.

The Australia they inhabit isn’t a “Crocodile Dundee” tourism board fantasyland but a multiethnic metropolis that looks remarkably like everywhere else in the world. It’s so rare that a movie treats its audience as if it can handle the way the world really looks, and the way people really act, that watching “Little Fish” feels like a treat. Like finally getting to sit at the grownups’ table.