Harry Potter & the Half Blood Prince SPOILER ALERT!
Chapter Eighteen: Birthday Surprises
Synopsis
During Potions class, Harry manages to remain the Professor's favorite by using the tips scribbled by the 'Prince'. At the end of the class, Harry tries to convince Slughorn to tell him about the real memory, but failed.
They have their first Apparition class. Harry positions himself behind Malfoy. He overhears Malfoy, Crabbe, and Goyle discussing something suspicious. Later, Harry decides to make use of the Marauder's Map to locate Malfoy -- but realizes that there were times that Draco seems to 'disappear' from the map.
In this chapter, Ron finds out that he is unable to celebrate his birthday in Hogsmeade. For some reason, Ron ends up eating the Chocolate Cauldrons Harry has stashed away. Ron starts to think that he is in love with Romilda Vane. Harry realizes that the Chocolate Cauldrons were his. He takes Ron down to Slughorn who cooks up the antidote.
After giving Ron the antidote (and since it is his birthday), Slughorn decides to give them a drink of mulled mead he was intending to give Dumbledore as a gift. They soon realize that it is poisoned. Harry, remembering the Prince's notes, looks for a bezoar saves Ron.
Theory: Draco snuck in the Christmas party and poisoned the mead intended for Dumbledore.
Rambling Gypsy