Set aside any preconceived ideas about I, Claudia — a one-woman show with Michelle Polak using masks to play four characters. You’ll want the full 90 minutes to figure out how she does it.

The one-act play follows the 12-year-old Claudia, who’s struggling with her parents’ divorce. The play exposes frank discussions on puberty and neglect.

Polak transforms seamlessly into each character. In her first role change, she goes from a heavy breathing, Bulgarian man to the awkward and animated 12-year-old Claudia. The shift in body language happens naturally, as she shimmies out of her men’s clothes onstage to reveal Claudia’s clothes beneath. She’s suddenly a preteen girl, pulling at her sleeves and fidgeting with her hair. The variety of mannerisms and gestures are well studied.

Polak wears masks that cover everything but her mouth, using her jaw to make the masks look like part of her face.

Claudia’s lack of inhibitions is hysterical, pumping her skinny limbs in front of the mirror to Katy Perry’s “Teenage Dream.”

But, there’s hurt and confusion.

The three other characters showcase a plurality of relationships between genders and generations. Her father doesn’t pay any attention to her. The school janitor is her closest friend.

Leslie, the dreadful stepmom-to-be, is set up as the villain. She’s a self-obsessed home-wrecker, who’s the root of Claudia’s neglect. But without the droning banter and high heels, Leslie is vulnerable in a way Claudia can relate to.

Subtleties in the script unearth a rawness and Polak delivers on the details to make each character human.

In the minor role of Claudia’s grandpa, the actress nails the age-specific comedic timing —spending three minutes patiently unwrapping a candy.

The point of I, Claudia is to see Claudia finally release her anger. When Polak delivers this much-anticipated burst, you’re emotionally exhausted.

I, Claudia plays tonight until Saturday at 7:30 p.m., with a matinee on Saturday at 2:30 p.m. at the Baby Grand Theatre. Tickets are $39.