Ah, the honeymoon period. That blissful, intoxicating point in a relationship when everything is going just right: you never fight, you laugh at everything and you can’t get enough of each other.

But of course, it never does last long enough. And for the couple in Candy, the troubles that come after the end of their honeymoon period are harder than what most couples encounter.

Based on the novel Candy: A Novel of Love and Addiction by Luke Davies, Candy tells the tumultuous story of Australians Dan (Heath Ledger) and Candy (Abbie Cornish) as they fall deeply in love — and heroin addiction.

Through the movie’s three chapters (heaven, earth and hell), we see how their drug addiction grows to consume more and more of their attention. Out of work and out of money, the couple starts selling their belongings and then stealing more items to sell in efforts to get some cash. Eventually, Candy turns to prostitution to finance their addictive habit while Dan sits idly, waiting for her in the car.

The redeeming feature of Candy and Dan is that they aren’t just in love but are truly loyal to each other. But as they grow more dependent on one another, they also become increasingly dependent on heroin. Despite their love, they destroy one another’s lives. Fighting one night, Candy hurls an object at Dan, causing his head to bleed and landing him in the hospital. But this only brings them closer, and they spend the rest of the night having passionate sex.

Both Ledger, who checked himself into a rehabilitation clinic in preparation for the role, and Cornish give believable performances as junkies struggling to sustain their never-ending need for more — more of each other, and more heroin.

Ledger, who has seriously improved as an actor since his days in A Knight’s Tale — as his Oscar nod will tell you — plays Dan with real depth. Dan is not resigned to the life he has, but he sees opportunities for change and goes after them. He wants to get clean and be with Candy. As he yearns for a different lifestyle, you sincerely hope that he can succeed.

The film exudes a strong pain and reflects the reality of heroin addiction, showing a window into the life at the bottom of the socioeconomic pile. Candy’s parents, Jim and Elaine (Tony Martin and Noni Hazlehurst), are always supportive of her, but watching Candy’s behavior, you can see the cost of her lifestyle on the parents when their child gets stuck on the wrong track. You share their grief as their little girl spirals out of control.

Geoffrey Rush plays a gay drug dealer, Casper, who provides the young couple with their goodies and frequently helps them buy their way out of trouble. But Casper leaves you wanting more, as he never quite lives up to the strong convictions you believe he has somewhere underneath those drug-filled veins.

Candy tells a good story and the audience is deeply involved as the characters go through their highs and lows, but after multiple scenes of shooting up, prostitution and agonizing withdrawal, it is too disturbing to really enjoy.