A sickening crack rang out, followed quickly by a scream that echoed throughout the dank chamber. The sound of muffled thumps and sharp cracks continued for a while longer, the screams becoming more and more half-hearted, until they faded away into pitiful, hoarse sobbing. To break was a nice way of putting it, but this wasn't breaking. He'd broken a long, long time ago, this was just dealing with the seemingly never-ending pain. Emotional or physical, he wasn't quite sure anymore, both forms of torture seemed to fade into each other and he couldn't be certain whether they were emotionally penetrating his sore mind or thrashing his poor, weakened shell.

Thor was pacing up and down, his great footprints nearly shaking the whole floor. The Avengers were gathered in the main area of the Avengers tower, clustered around the room, having had Thor arrive on the roof only around half an hour ago, bearing news that Loki had escaped and was thought to be somewhere on Earth. Steve frowned, confused.
"But I thought you said that the prisons were completely secure? No one could get in without special access and no one could get out?"
Thor nodded furiously.
"Exactly! That is why we cannot fathom an idea as to how he escaped!" his tone was feathered with hysteria as he ran a hand through his hair.
"Then someone let him out?" asked Natasha, narrowing her eyes.
Thor shook his head, "No. We would have known if the cell had been opened." he took a calming breath, "It had not."
"Then how…?" Steve let the question trail off, unanswered – until…
"He's a crafty little s-"
"TONY!"
"-t, that's how." Steve cut Tony off mid snarky answer with a meaningful look to Thor, whose eyebrows had knitted together. Tony held up his hands in surrender.
"Oops, sorry, your Highness. Just adding a viable suggestion to how your moron of a brother managed to break free from his chamber of doom." Clint hurriedly disguised a chuckle as Thor threw him a stony look. Natasha wiped away her own half-smile and stepped forward.
"In all seriousness, we need to find him. Before he does more damage." The others nodded, except from Thor, who's thunderous rage did not seem to be going away.
"We searched Asgard from top to bottom, around every corner, every bend, every haunt that Loki favourited – Hemindall looked around many different realms until he sensed a brief signal coming from here! And now we must search the Earth until -"
"We're not that desperate, are we?" Tony lazily fell back into one of the bar stools and swung around, unaware that he'd built Thor's temperature even higher.
"HOW DARE –"
"I think, perhaps, we should lower the volume a little."
Bruce, who had been rather quiet until now, unfolded his arms and stepped away from the window. Miraculously, the atmosphere died down and the anger simmered gently, not bubbling over has it had started to do. The worry returned to Thor's eyes and he frowned, nodding.
"He's right. It'll do no good to quarrel amongst ourselves. If we're to find Loki…" he stopped, swallowing before this next part, "… alive – then we must start now."

It took about a week. To find him took about four days - endless tracking signals and mechanical devices, manufactured by Bruce and Tony. Then they spent three more days' clever map-working and defence ideas from Clint and Natasha and a smart plan of action, drawn up by Steve and Thor.

"Now," Thor began, "We don't know who these people are, or what they want from Loki… So we must be careful. He may have chosen to go willingly – or this could have been his plan all the time…" Thor added in a low undertone.

It took them what seemed like forever to find the place where Loki was – and when they did, neither of them spoke for a minute or two.
It was huge, crumbling building, stretching up high. The Avengers stood in the alleyway, peering up at the rotting wood that was beginning to show through the holes in the brick. This back entrance had altogether surprised them as, from the front, the building looked pristine and perfect and made of stone.
"It's a perception filter," muttered Thor, explaining when Steve shot him a confused look: "It's not real. It's just what they want you to see."
"Advanced technology," Tony sounded impressed, "Very, very advanced..."
"Not advanced enough to stop us getting in the back way, though," Natasha stepped forward briskly and clicked the door open with force.
"Well, that's going to leave a dent," Tony remarked as they filed through it, sticking to the wall and hurrying along into the darkness.

The tracking device which they had locked onto Loki's last signal lead them down a few flights of stairs. With them having entered on ground level, it was now apparently that they were several hundred feet below. At the bottom of the staircase, they found a huge wall, with a small tunnel entrance.
"Clearly, these monsters that accompanied your brother are huge," Tony said, jauntily as he squeezed the suit through the gap. Thor didn't appear to hear, checking behind him as he ushered them all through and squeezed through himself. The tunnel, covered with green moss and worn walls, sloped downwards even further, causing smart remarks from Tony -
"Are we at the centre of the Earth, yet?"
"Is it just me, or is it getting hot in here?... Oh yeah, it's just me."
"Oh look, Thor, these lights make your hair shine -"
However, he was cut short halfway through a joke about sunburn when the sound of a scream reverberated through the tunnel. Its sharp arrival struck the air, causing an icy silence to fall over the team. They hadn't realised they'd stopped in their tracks until more screams caused Thor to break free of the trance, muttering "Loki." and sprinting off into the darkness.
"Oh crap, what light are we supposed to use now goldilocks has ran off with his shining hair?" Tony increased the suit's brightness as they followed Thor, who was now thundering along at an incredible pace. Steve, Natasha and Bruce reached the door and skidded to a halt behind Thor who had halted, apparently waiting. Tony and Clint were the last ones running and Tony noticed Clint slowly fall behind, his face set in stone, a glum expression as they both slowed to join the others.
"Wait," Natasha put out an arm to stop Thor, her voice hushed and barely audible, "They're still in there. Just wait and we can have a clear path."
"She's right," Bruce looked at the device, "Their signals are fading now, they must be transporting out somehow, so we've got a free path, if we just wait…" Thor nodded.

Of course, it was a mere matter of seconds, but for someone who's waiting, it seemed like forever. Finally, the coast appeared clear and Bruce nodded to Thor, who had sung open the door and strode in in a matter of seconds.

At first glance, the room appeared empty. The walls were damp and the only light came from a window high up in the rafters of this strange, underground chamber. The light from the window was clearly artificial as it glowed a dull green colour – and, not to mention, they were down hundreds of feet. It wasn't until the pile of rags on the floor gave a small sigh that Thor realised where his brother lay.

It was bad enough seeing the evil genius that had almost succeeded in taking over the world lying, battered and bruised and covered in blood, curled up on the floor – what was worse was the way he reacted when Thor threw himself down beside him and tried to cradle his lost brother in his arms. The once magnificent being hugged himself tighter and hid under a mass of matted black hair. He shook, although whether it was from cold or fear, it was hard to tell.
Even Tony was struck-dumb at the state in which the smart little git had got into.
"Come on," Bruce laid a hand on Thor's shoulder, "We need to get him out. Now."