Back in the dorms, Ron is acting really strange and moony (like, he's literally staring at the moon), saying he thinks he's in love with someone.
Harry assumes he's talking about Lavender. After all, isn't that who he's been "snogging," as the Brits say, for the past three months?
Guess again: Ron says he's gaga for Romilda Vane. Remember that name? She's the girl Hermione had said was trying to sneak Harry a love potion. Hey, wait a second…
Yup: Harry sees that Ron had opened a box of chocolates he found on Harry's bed from Romilda, and realizes that his buddy was under the power of a love potion intended for him. Oh, dear.
But…wouldn't this be the perfect opportunity to hit up the Potions professor for help? So, Harry takes Ron to Professor Slughorn, and this time he doesn't get the door slammed in his face. Things are looking up.
While Slughorn is preparing the antidote, Harry takes the opportunity to apologize. Slughorn says don't worry about it, it's all water under the bridge. (But he still does not like Harry saying the name Voldemort out loud.)
Aww, peace comes to Hogwarts. Ron drinks the antidote and, a second later, snaps right out of his potion-induced mooniness.
To celebrate, Slughorn pours them all a drink, which Ron barely gets down before collapsing on the floor while foaming at the mouth. What the what? Did Slughorn just poison Ron after saving his life?
Slughorn has no idea what happened and just stands there in shock, while Harry struggles to figure out how to help. He rifles through the professor's drawers and luckily, he finds something called a bezoar, which saves Ron. Phew.
But it was touch and go for a minute there—who would have thought Hogwarts' worst Potions student would be thinking faster than the Potions teacher?