A/N: This is my first ever crossover fanfiction! I absolutely adore Death Note (and Lawlight!) and I'm a longtime Potterhead so it's long overdue. Hope you like it!

Disclaimer: I do not own Harry Potter or Death Note or any of the characters, this applies for all chapters. I also do not own the cover image, which I got from Pinterest (credits to all due!)

Chapter 1: The Cruciatus Curse

"Raito-kun, let's try calling Ryuk again."

L was pissed. Really pissed. It had been three days since his last piece of cake, so he was probably going through sugar withdrawal on top of everything. Light noted his deepening scowl with some amusement. So that emotionless mask was just a façade after all. Light had always known that, but it was nice to get some confirmation of it.

"Look, L, it's not my fault we're stuck here, alright? I didn't ask Ryuk to open a portal into nowhere."

L glared at him. "Well, you're the one who asked him to show you the Shinigami realm in the first place!"

"You didn't have to come too! I never asked you to."

The detective pouted, and Light was sure it was the most unnervingly adorable thing he had ever seen. Quietly, L pushed his fringe out of his eyes.

"I was…curious."

Light scoffed. "Yeah, right. You're not fooling me, L, you came along to keep an eye on me. Well, this is what you get. Go on, keep your eyes on me, but don't complain about it."

L sulked, trotting along to keep up with Light's easy strides. They had been wandering through the forest for three days. "Raito-kun, eventually the food in your pack is going to run out."

The teenager gave him a heated look. "Honestly, L, if you don't stop complaining, I'm going to ditch you. Then you'll be sorry for forcing yourself on my adventure in the first place!"

"I'm already sorry." L muttered.

"Well, good! You deserve it."

They walked in silence for a bit, and Light was sure L was in the foulest mood he could possibly be in. So he was in for a surprise when L finally opened his mouth again and his tone was soft, wistful.

"Raito-kun…you know I would never have let you go alone."

The younger man blinked at him. L's cheeks were flushed, and he was avoiding eye contact. Light looked away, but a huge smile grew on his face. "Yeah, well, if I had to be here with anybody, at least it isn't Misa."

L glanced doubtfully at him, but a few seconds later, Light found a soft pale hand in his.

He was just about to say something, giving the hand a squeeze, when they heard an ear-splitting shriek coming from their left. Without actually thinking about it, Light pulled the butcher's knife (the go-to weapon he had grabbed before they left with Ryuk) from his belt and instinctively shoved L behind him.

"Light, we have to get to higher ground, it could be a wild animal, we don't even know what region we are in. Come on-" L's frantic tirade was interrupted by that same scream, but much worse this time, unending and stretched thin with pain.

"L, we should check it out." Light whispered urgently, tightening his hold on L's hand and surging forward. L didn't resist, quickly catching up with him as they weaved through the trees, getting closer and closer to the source of the scream that had devolved into choked sobs.

They finally came upon three teenagers standing around a tree, another, heavier teen pressed against the tree trunk, writhing in pain. One of the people surrounding him, a reedy boy in a green robe, raised a slender stick in the air, the end of it glowing crimson. The boy in the middle responded by letting out a quiet, shuddering wail, collapsing to his knees.

Light slipped off his pack, shoving it into L's hands. "L, careful with this. I hid the Death Note in the third flap. Keep it safe, I'm going to help him."

L snarled, shoving it back. "What makes you think I'm going to let you walk into what looks like a cult ritual with a butcher's knife, Light?"

"I'm not going to kill them, L, I'm going to save him!" He hissed, exasperated.

L grabbed Light's sleeve, pulling him back. "I'm not afraid you'll kill them, you idiot! We're alone in the middle of the woods, don't you dare-"

"Who the bloody hell is spying on us?"

It was a thick British accent. Light pulled his sleeve from L's grip and gave him a scornful look before stepping into the line of sight of the bullies.

He cocked his head as the green-robed cultists regarded him, giving them his most smug, charming smile. "I've called the police. You assholes better get the fuck out of here, leave him alone." Light squeezed the handle of his knife, knowing all too well how slippery it was in his grip.

The bullies' eyes boggled. "That's a muggle!" Slowly, huge grins grew on their faces.

Light narrowed his eyes, letting the blade of his knife flash in the meagre light. "Look, just back off. The police are-"

"Crucio!"

Light's mind grew entirely blank. There was a buzzing in his fingertips, and every nerve in his body was aflame. He couldn't see, he couldn't think about seeing. His ears were roaring with blood, blocking out anything he could have heard…blood, he should have been bleeding or crushed and mangled by a boulder or burning to death in a wildfire. Nothing else could possibly explain the pain. All he could see was a faded, glowing red under his eyelids, his every nerve screaming at him, white-hot, just screaming.

And then his cheek was pressed against the damp grass. The cool air chilled the sweat over his body and his nose was filled with the sweet, warm smell that reminded him of cake, cookies and mind games played while cuddling in bed. It was more comforting than he could possibly say out loud.

His hearing started to work again, and he could hear L shouting at the top of his lungs (he had never heard L shout at anyone but himself or Matsuda before). "Bastards! Yeah, run, you fucking cowards! Get the fuck out of here!" L's arms suddenly enveloped him, and Light realised he had forgotten to open his eyes. He blinked up at L, who was holding him tightly to his chest.

"Raito-kun, are you alright?"

The fog in Light's brain began to recede as he sank into those huge black eyes. "Yeah. Yeah, I'm fine." He managed to croak, his throat felt sore and papery, as though he had either been screaming or crying. "I don't actually know what happened."

L's hand supported the back of his head, rustling his auburn hair. "They ran off. After they shocked you with whatever weapon that was, I hit one of them with a rock. They tried to shock me, but the backpack deflected it. I threw another rock, and they ran away."

Light, unexpectedly, grinned. "I've never seen you that angry. Not even when I confessed to being Kira."

L smiled, loosening his grip on Light and running his fingers through the boy's sweat-dampened fringe. "Obviously, Raito-kun-"

"No ordinary backpack would deflect an Unforgivable Curse." The kid they had both forgotten about, the one who had started this whole mess, was getting to his feet. He walked up to L with a slight limp and stuck his hand out in front of the detective's nose.

"Neville Longbottom."

L considered the hand, but opted to keep both of his around Light. "Ryuuzaki."

The large boy, who looked pale and malnourished in the evening light, wrinkled his nose. "Ree-yoo-what?"

Light chucked weakly. "His name, it's Ryuuzaki."

"Ryuuzaki, alright. And you?"

"Light Yagami." Light cleared his throat.

"Right, so you're Japanese, then. Have you…have you come to help?"

Light shrugged. "Well, you were screaming…"

"No, not with that. Thanks for that, though. I meant…with the War. With the Order."

L groaned. "Of course we had to end up in the middle of a war. Raito-kun, we have to call Ryuk!"

"Calling him doesn't work, Ryuuzaki! He doesn't answer!"

Neville blinked. "Ryuk? Is he another Japanese wizard?"

L gaped at the taller boy. "Wizard?"

"…yes. Wizard."

"Wizards exist here?"

Neville stared at the two men in front of him. "Are you two muggles or what? How on Earth would two muggles have deflected a Cruciatus curse?"

Light stared at him, then dived for his backpack, wrenching it from L. "Fuck, fuck, fuck." He rustled through it desperately, hoping against hope that whatever L had deflected with it hadn't done anything…until his fingers closed around the spine of the Death Note and he let out a sigh of relief. "Oh, thank God."

Neville peered curiously at him. "Are you carrying a magical object?"

Light shook his head, snapping his backpack shut and pulling it on. "No, it's just that all of my stuff is in here. Didn't want anything getting damaged. Mr. Longbottom, was it? Do you know where the nearest place to stay is?"

Neville frowned, glancing to his left. Light followed the line of his gaze, and his mouth dropped open.

"Is that… a castle?!"