Aglaya meets Myshkin when he comes to introduce himself to her mom.
She gets a note from Ganya, who is trying to hedge his bet with Nastasya by also leaving the door open with Aglaya. Aglaya is not a fan of this maneuver and sees right through him.
Six months later, Aglaya and Myshkin meet again in Pavlovsk.
She starts falling in love—or something—with him because of his daily visits, although she mostly just mercilessly teases and mocks him. At the same time, she is being courted by Radomsky, a wealthy, but slightly sketchy ex-military guy.
Sometime after Ippolit's confession, Aglaya learns that he dedicated it to her and she starts corresponding with him.
Aglaya feels harassed by her family about Myshkin, because they are all dying to know will-they-or-won't-they. She responds by throwing childish tantrums and generally acting out. This goes over poorly.
At the same time, she arranges to meet Myshkin alone in the garden near her house. They talk about nothing in particular, but clearly this is deeply meaningful.
She starts receiving letters from Nastasya, who writes to try to convince Aglaya to marry Myshkin.
These letters reignite the main issue standing in the way of Aglaya committing to the prince—she is crazy jealous about whatever relationship he had with Nastasya.
Aglaya sets up a meeting with Nastasya and drags Myshkin along for the ride.
At the meeting it's not really clear what Aglaya wants, but she starts to tell Nastasya about everything that's wrong with her—and actually, she is super-duper dead-on accurate.
When Myshkin can't help but go to Nastasya, Aglaya dumps him and refuses to ever see him again.
A few months later, she runs off with a Polish count in political exile. He turns out to be none of these things, and Aglaya grows apart from her family.