In a flashback dream sequence, we see Regan's dad talking about how he just got a promotion at Sears—as a treat, he's buying their mom a new washer and dryer. Diamonds are forever, but a washing machine's just way more useful.
All the boxes are huge, obviously, so Liam (Regan's brother's given name) grabs them and tells Regan to set up a fort. Liam wants to play the mommy, as always.
Then Liam grabs Regan's doll and starts to change her clothes.
Regan in the present wakes up to the sound of her alarm, and thinks about if she ever had a moment when she knew that Liam was transgender.
After she showers and gets to the kitchen, she sees that Liam is sitting at the table in his boy clothes.
Their mom is flittering around answering phone calls for her wedding planning business, which their dad isn't too pleased with since he wants to be the man of the household and bring home all the bacon.
Dad starts telling a pretty dumb joke, which is apparently something he does at breakfast each day. Teenage eye rolls commence.
Then Dad throws a curveball—he tells Liam that he talked to Coach Hewitt and wants Liam to go sign up for the baseball team.
When Liam protests, Dad tells him that he has to go.
Mom butts in to say that she's going to be late and that Regan should start making dinner. They sure are big on gender norms in this family, right?
When Regan says that she has to babysit, Liam says he can cook dinner for her, but their parents get upset because it's Regan's job as the girl to cook.
Things get pretty tense and the kids get up to leave. Regan asks Liam if she can catch a ride with him, but he runs out to the car and leaves without her, looking at her with hatred. What gives?
Regan gets a flashback to Liam's ninth birthday party, when he has a joint party with his best friend, Aly.
Liam asked for a bra and a Prom Barbie, and when he sees their dad whirling Regan around like his little girl, he looks at her with sheer hatred.
Regan realizes that Liam wants what she has—he wants to be daddy's little girl.