Hermione and Draco want to be together but her friends (e.g. Harry, Ron...) and his "friends" (e.g. Snape, Zhabini...) are against it. But they still love eachother and Draco invites her to the yule ball. Harry sees it and begins a fight with Hermione and Draco. At the yule ball Hermione and Ron argue about her and Dracos realationship. Then she suffer it anymore and cries in her bedroom and thinks about her friends and her truly love. Draco sees that, goes to bed and thinks that he must choose his friends or Hermione. He decides Hermione and goes to her but Harry hexes him but when he sees Hermione he disenchants Draco. Hermione begs Harry to admit her realationship with Draco and because Harry doesn't want to see Hermione unhappy anymore accepts it.
1.34 - 1.36 in that scene hermione and ron are speaking russian. for the people who don't understand russian: ron is saying: you're friends with the enemy; hermione says: with the enemy?