Harry, Ron, and Hermione are captured by Snatchers

"The name's Taboo! I told you, Harry, I told you, we can't say it anymore -- we've got to put the protection back around us -- quickly -- it's how they find --"
-- Ron Weasley, cut off by the Sneakoscope coming to life (DH22)

After receiving an emotional high from hearing familiar voices and support on Potterwatch, Harry accidentally lets slip Voldemort’s name, which is taboo to speak. It breaks all of their protective enchantments and brings a group of Snatchers, led by werewolf Fenrir Greyback, to the Trio’s location. An article in the Daily Prophet tips off the Snatchers that they have caught Hermione Granger “who is known to be traveling with Harry Potter” (DH 23). Wanting to reap the 200,000 Galleon reward for Harry’s capture Fenrir decides that they must bring their prisoners, which include Dean Thomas and Griphook the goblin, to Malfoy Manor so that the Death Eaters can summon Lord Voldemort.