Hermione was on her way to Hagrid's cottage when she found the wand. A dozen steps later she found-
He was splayed awkwardly on the ground, face-down, flailing weakly and gasping for air. Hermione grabbed the wand and ran to put it in his hand. "Professor - do you need help? What happened? Are you-"
She didn't see the circle traced in the grass until she was already across it. She was still a hand's-breadth away from putting his wand into his grasping hand when she started choking on the noxious smell in the air. She doubled over, coughing, but something landed on her back and knocked her flat before she could catch her breath. Something with sharp heels, which it dug gleefully into her sides as she frantically tried to fill her lungs. The creature giggled madly, the sound a high-pitched hum in the chilly evening air. Hermione forced her head around so she could see Professor Snape - and immediately saw what had to be a second creature sitting on his back as well. Something with long limbs and a grotesquely contorted body, which kept fading in and out of view . . .
"Here now, stop that!"
Hagrid's booming voice cut through the buzzing in Hermione's ears. She felt the oppressive cloud ease a bit - not all the way, but enough she could draw in a strangled breath. Somewhere in her peripheral vision she saw the toes of Hagrid's immense boots stop just short of the inscribed circle.
"They're higglewumps, Hermione!" Hagrid yelled - totally unnecessary since he was practically right next to her, but the noise roused her a little bit more. "You gotta - here, repeat after me! Silimus clevari cadarenti nostarum!"
Hermione tried to shout the words back, but all she managed was a whisper. Still, that should count, right?
"You too, Professor!" Hagrid boomed as he circled around to where Professor Snape could see him. "Give your pledge!"
Professor Snape narrowed his eyes at Hagrid, but he gasped out a similar string of syllables. And immediately the pressure on Hermione's back vanished. She dragged in a deep breath and turned to thank Hagrid-
But the creature on Professor Snape's back wasn't getting up. Hermione realized she was still holding his wand in addition to her own, so she nudged the end of it into his hand. Professor Snape muttered something under his breath, flicked the wand weakly, and suddenly the circle and the creatures and the oppressive smell were just - gone. He got to his feet, breathing heavily.
"What exactly did you think you were doing, Miss Granger?" Professor Snape asked.
Hagrid cut in before she could answer. "Pretty obvious, that - she was trying to save your life."
"My life was perfectly safe."
Hagrid snorted. "You had two higglewumps on your back and they managed to disarm you, Professor. How did you come by higglewumps, anyway? That's one creature I've always wanted-"
Professor Snape gave him a withering look. "They serve pureblood families, Hagrid."
"-which is why I never thought I'd have a chance to get so close to one. Lords, Hermione! What did it feel like?"
"The real question is," Professor Snape interrupted, "what are we to do now?"
Hermione jumped in before either of them could interrupt her again. "I, for one, would like to go back to my room and go to bed. Hagrid, I was coming by to say hello, but I think that was about all the excitement I can take for one evening."
Professor Snape suddenly looked uncomfortable. "It's . . . not that simple, Miss Granger."
Hagrid cleared his throat.
"Sorry. Mrs. Snape."
Hermione blinked at him. Hagrid was backing away, obviously unwilling to explain, but -
"One of you better tell me what's going on," she said with as much authority as she could muster. "What was that spell, Hagrid, for one?"
"It was, ah . . ." He rubbed the back of his neck. "A wedding vow, actually. Only way to rescue you from the higglewump. Bound to you now and all."
Hermione could feel her mouth drop open, but she couldn't be bothered to close it. She turned to Professor Snape for clarification, but he wouldn't meet her eyes.
"Higglewumps are bound to pureblood houses, much like house elves," Professor Snape said quietly. "Those two came to me recently from my mother's line. I'm sure Hagrid was only trying to help."
"But what happened?" she demanded.
"You joined my house," he said with a hint of a sneer. "Those were marriage vows, as you would have already known had you been listening. Happy wedding day, wife."
Hermione didn't feel her legs buckling under her, just saw a sudden motion out of the corner of her eye and then Hagrid was lowering her onto the grass.
"I'm so sorry, Hermione," he said with real tears in his eyes. "Once a Higglewump traps you, you're caught for good. Even if you manage to shake it off, it has gained the - magical right, I suppose? - to hunt you. It can get past all sorts of magical barriers to catch you again. Including those at Hogwarts." He looked up at Professor Snape. "I assume that's how they got onto the grounds, Professor?"
The professor nodded curtly. "That one . . . knocked me down once when I was a child, visiting my grandparents' house. It has come after me on occasion ever since. I got word the two were tired of waiting for me and were coming to Hogwarts through the forest, so I came to head them off, so to speak. I . . . was not expecting them to be lying in wait."
"But why did you trick us into getting . . ." Hermione couldn't force herself to finish the sentence.
"Married?" Professor Snape asked acidly. "I would like to know the same thing. Surely you could have helped her temporarily, Hagrid?"
Hagrid shook his head. "You may know potions and dark arts and whatnot, but I know my magical creatures. And Miss Granger - sorry, Mrs. Snape - wouldn't last a week once those things were after her, even here. Sorry, Hermione," he added, "but it's true. The only way to keep them from killing you was to become part of the house they serve. And since they had only winded Professor Snape and hadn't actually killed him, I knew they must be bound to him. His house. And now they're bound to you."
"But I don't want to be married!"
Professor Snape sneered. "That makes two of us, Miss Granger."