When you go to see Precious, bring some tissues. This movie, set in 1980s Harlem, is not a sunshine sing-along. It's the story of Clareece "Precious" Jones, an overweight and illiterate 16-year-old eighth grader who is pregnant with a second child (both the result of rape by her father). Her mother, played brilliantly by the-usually-funny-and-personable-but-suddenly-terrifyingly-cruel Mo'Nique, blames her for everything wrong with their lives, and is both verbally and physically abusive. Over the course of the film, more hard hits come and the darkness is suffocating for both Precious and the audience.

So why are we hearting this film, you might ask? First, because it's important. This is a story that's worthy of being told. Second, because Precious herself is absolutely raw and endearing. When she daydreams, she glows -- imagining herself on the arm of a boyfriend who cuddles her, as a fashionista, as a movie star. Her imagination keeps her alive among the horrors of her home. And third, because there are people all around the world -- of all shapes and sizes and colors -- who do battle demons like these.

Discovered in an open casting call, lead actress Gabourey Sidibe is riveting as Precious. Mariah Carey's turn as an overwhelmed social worker with a slight mustache is also impressive (I'm serious -- both about her good acting and the mustache). And yes, there is a sliver of light at the end of the tunnel. Actress Paula Patton plays Ms. Rain, a compassionate pre-GED teacher who is all business with Precious and helps her make some strides with her education. And there are even a few laughs in the film, with actress Chyna Layne standing out as a bubbly classmate and Lenny Kravitz as a kind nurse in the hospital where Precious gives birth.

This film is rated R for a reason -- it's not for the faint of heart, but it's still full of hope. Precious opens today in select cities.

Watch the trailer here: