DISCLAIMER: I do not own Percy Jackson/Heroes of Olympus, all rights to Rick Riordan! I also don't own The Avengers either, so rights go to Marvel or whatever

ANOTHER IMPORTANT NOTE: Earlier on we saw a short scene with Agents of SHIELD characters, and I said I hadn't seen season two yet so it would only be season one. But that was like a year ago and now I've seen season two and really want to add them, so…Yeah, season two characters in upcoming chapters. And if you don't know them, don't worry. Not a big deal.

And also: Dark!Percy is ahead!

"They can't get in, right?" Nico demanded, intense dark eyes staring up at Annabeth. "They're not half-bloods, so they can't get past the borders. We have an advantage."

The son of Hades and Will had just gotten back from their trip to the beach, out of breath from running. When Annabeth had asked if the gods were coming to help, Will simply shrugged.

"They accepted the offering. That doesn't say much, though. Who knows what they'll do. We just have to hope." The son of Apollo's eyes were constantly in motion as he said this, one minute on the swarm of demigods in front of the border, the next on his cabin mates rushing around tending to a few of the already wounded.

Annabeth nodded quickly. She continued to quickly brief Will and Nico on the situation. "Whatever you do, don't leave camp. They can shoot at us, but they can't get in." She looked up toward the firefight at the border, anxious. Percy was over there, she knew. She could hear him shouting commands at his fellow warriors, encouraging them. The Legion was already swarming toward SHIELD's left side, cutting them off before they could surround Camp Half-Blood any further. At least a dozen demigods zipped by overhead, throwing any magical item they could get their hands on into the crowd of soldiers below. Captain Rogers was on the front lines, using his shield to deflect bullets and knocking out soldiers left and right. Annabeth was glad he was on their side.

"Stick to the plan," she told the two demigods standing in front of her. Nico was holding his Stygian sword, thanks to a little trick Hazel managed to figure out. She was able to enchant a few demigods' weapons with the ability to hurt mortals temporarily just before the battle. She'd offered it to Percy, but he'd declined, saying he didn't want human blood on Riptide. He had, however, accepted a regular sword. Annabeth grasped the heavy gun her boyfriend had given her so tightly her knuckles turned white. "Let's get 'em."

The three demigods charged toward the group of fighters, dodging stray bullets and screaming their battle cries. Annabeth had just caught sight of Jason and Piper standing by Thalia's tree, firing off round after round from their semiautomatics, when the magical border surrounding the camp shimmered. The demigods stopped in their tracks, looking skyward to where the shield was turning a deathly shade of purple and shattering. The gunfire had stopped on both sides, the world ominously quiet.

"No…"Annabeth murmured, watching as fragments of the shield fell away and winked out of existence before they hit the ground. She pushed her way to the front of the crowd, coming to a stop next to Leo. The Avengers were standing right at the edge of camp, one of them—Black Widow—holding a small vial full of glowing red liquid.

"Not possible," Leo muttered, his oversized war hammer hanging limp in his hands.

Nico and Will were suddenly standing next to Annabeth and Leo, both equally stunned.

Black Widow, Hawkeye, Ironman, and Thor stepped across the now broken border. Mortals were inside the camp.

Nico gasped as soon as their feet touched earth, staggering back a step. He suddenly dropped his sword, hand gripping his wounded arm. The old wound was completely healed, nothing left but a thin scar, but still Nico breathed heavily, sagging back against Will.
"Nico? Are you okay?" Annabeth demanded, shooting a concerned look toward Nico. "How are they getting through?" Her voice was urgent.

Will shook his head as the Avengers stood their menacingly, waiting for the demigods to react. "How could I be so stupid?" He was holding Nico up by his good arm, and thankfully the son of Hades seemed to be recovering slightly. He rushed on. "If a mortal has the blood of a demigod, they can force the border to open for them. I read about it in one of the books Chiron lent me. It has to be an extremely powerful demigod, but it is possible."

"So whose blood are they using?" Annabeth was trying to keep her cool, but none of her plans had allowed room for this. As soon as the words left her mouth, Annabeth figured it out. There was only one person who had been injured and unconscious in their care for at least two days. They could have done anything they wanted to him.

Nico was still gasping for air, although he had picked up his sword again and wasn't leaning on Will anymore. His expression was full of dread. "I think it's mine."

"It must be blood from the wound you had on your arm," Will muttered. "That's why it affected you like that."

"Last chance. Stand down." Ironman's faceplate was up, and Annabeth could see his face. His expression was impossible to read.

Stark's voice broke the blanket of shock covering the demigods. Percy rushed forward, a mortal sword in hand, running straight for Black Widow. The group of demigods followed suit immediately, charging into battle.

Percy lunged forward at the assassin, his sword just missing her side as she ducked out of the way. He flashed back to their fight in the street so long ago and remembered exactly what she'd done last time to disarm him. This time, he was ready as she kicked her leg out and tried to trip him up. He hopped over her foot and brought the hilt of his sword down hard on her previously wounded knee. She barely showed any acknowledgement of pain as she caught Percy by the wrist, pressing down hard on his pressure point. He kept his grip on his sword tight, knowing he would drop it in a matter of seconds if he couldn't break free. Unfortunately, Romanoff knew just how to hold his arm so he couldn't break free, and his sword slipped from his hand. She twisted his arm behind his back, and Percy gasped in pain. He struggled, realizing just how well-trained this lady was. He brought his leg forward and kicked her hard in the knee once again. She staggered a little, but still managed to grab a nasty looking gun from the holster on her thigh. Suddenly, a glittering bronze knife sailed through the air, lodging into Black Widow's arm. She jerked back in surprise, dropping the gun and hissing in pain. Annabeth raced forward, immediately engaging in hand-to-hand combat. Romanoff had yanked the knife from her arm and threw two punches in quick succession at Annabeth. The daughter of wisdom swayed to the side, throwing a roundhouse kick at Romanoff's ribs. Widow took a step backward, trying to regain her balance, then threw herself forward again at Annabeth. Percy jumped to his girlfriend's aid, the two ganging up against the master assassin.

The redhead stood, facing off the two demigods. "Two to one," she said. "Hardly fair."

She faked a punch in Annabeth's direction, then dove the other way toward the gun she had dropped earlier. It didn't look like a normal weapon, and Percy had the sudden realization that it must be one of their special ones. The ones that could take away a demigod's power for hours. The one that could paralyze its victims.

Her dive had taken her to the ground, and she was lying on her back now, both hands up and holding the Politician. Widow fired off two shots, both in Percy's direction, before Annabeth leaped forward and tried to knock it from her hands. She grabbed the daughter of Athena's ankle and yanked it to the side, knocking her to the ground.

Percy felt that familiar tightening in his gut, that tingling in his fingertips. Water rushed forward across the ground, making agents and demigods jump out of the way. He sent it soaring through the horde of SHIELD officers surrounding camp Half-Blood, washing several of them away. The water raced up into the air, forming a violent tsunami. Rainwater pelted the area around them, drenching the three warriors and shielding the two demigods from Romanoff's bullets. Percy could barely see her through the rainstorm crashing around them. Annabeth got to her feet beside him, touching his arm as he controlled the water, sending it spiraling into the air and curling around Romanoff. It was time to end this once and for all. They wanted a reason to fight him? Well here it was.

The water suddenly shot into Romanoff's mouth, zipping down her throat and choking her. She gasped for air, coughing up water even as she inhaled more. She threw up her hands, trying to shield herself from the cascading water rushing at her.

Percy's heart raced even as it grew colder, resolve hardening in his mind. He felt Annabeth clutch his arm tightly, not yet realizing what he was doing. Percy really did feel horrible. He almost couldn't do it—drown Romanoff. In all his years of killing monsters and being a hero, he'd never killed a human being. And really, he wanted to keep it that way. But wasn't she trying to kill him? He was trying to protect his home, wasn't he?

Annabeth grabbed his arm and yanked it, making Percy drop his concentration. "Percy, stop! You can't do this!"

"She's trying to kill us, Annabeth! All of us!" Percy screamed angrily, wrenching himself free of his girlfriend's grasp and putting his hands up again. Just as quickly as Widow had regained her breath, she lost it again.

A hot, stinging feeling suddenly flashed across his face, and he looked up to see Annabeth's blazing eyes glaring at him, her hand lowering back to her side. "Perseus Jackson you stop this right now or so help me I will hit you a lot harder than that." She was holding her knife in a shaking hand.

Their eyes met for a brief instant, in which Percy saw Annabeth's fear.

"Don't do something you'll regret." Her voice was firm.

But he wasn't going to regret this.

Just as he pressed the water on harder, burning heat flashed against his back, and he flew at least thirty feet, slamming into Thalia's tree with a crack. He heard Annabeth scream—in surprise, anger, or worry, he had no idea. Percy struggled to heave a breath into his empty lungs, sure that at least two or three ribs had cracked. He turned sea green eyes to see Ironman standing in front of him, hand up and blazing with power, ready to shoot again if needed.

"Stay down, kid," he said.

Percy dragged a few more breaths in. "That thing certainly...leaves you…breathless." He laughed a little. "Pun intended."

Stark snorted. "Nice one. Now look, I don't want to hurt you. But when you try to kill my friend here, that's when I get involved—"He was prevented from saying anything further as Jason suddenly flew down, summoning lightning to strike Ironman. Unfortunately, Stark just stood there expectantly.

"Yeah, sorry about that. See, I've made it virtually impossible for me to get electrocuted in the suit. Again, sorry to disappoint." Before he'd even finished speaking, he shot forward, lunging for Jason. Jason was in the air in a heartbeat, Ironman racing after him. The two battled in midair momentarily, then Jason began to fall. Stark zipped down, grabbed him, and flew back down to ground level. He dropped Jason on the ground next to Percy. He looked at Percy for a moment—the son of Poseidon couldn't tell exactly what he was thinking because of the mask. It almost seemed like regret.

Percy put two fingers against Jason's neck, checking for a pulse. His green eyes roamed the area, watching the destruction as he desperately tried to breathe again. It didn't help that fire shot through his veins every time he inhaled. Black Widow was now fighting three campers, looking a little overwhelmed. Percy searched the area for Annabeth. He felt a stab of worry when he couldn't find her.

It was chaos. Pure chaos.

Jason was still alive, thank the gods. He figured since Stark had been kind enough to set him down nicely, he hadn't killed him. Still, you should always make sure.

He got up and ran toward the fight again, snatching up his sword on the way. He ignored the pulsing pain in his chest. His eyes fell on Nico, who was standing in front of the Hades cabin wielding his Stygian sword. Three soldiers surrounded him, backing him up towards the cabin's porch. What was the problem? Nico could easily defend himself against a few mortal soldiers. Something was wrong.

Percy was forced to stop momentarily to knock out an agent assaulting him. He was down in a matter of minutes. Percy jumped at the first soldier he could, tackling him to the ground. The man twisted around, elbowing Percy in the mouth. He was thrown to the side, rolling in the dirt. He tasted blood. His sword had flown from his hand and now lay a foot away. The soldier slammed a foot down on Percy's wrist—thankfully not his sword hand—and twisted it ruthlessly. The son of Poseidon gasped in pain, feeling his wrist being ripped right out of its socket. The soldier leveled his rifle at Percy's chest. He wasn't aiming to kill, that much Percy knew. Otherwise he would have lined up the sights on his head.

Still, a bullet to the chest at point-blank range would most definitely kill him.

His fingers found his sword just in time and it arced up, catching his assailant in the shoulder. He screamed in pain, stumbling back and falling to the ground. Percy pulled himself to his feet and was immediately met with another agent. Percy was surprised when he saw her—she was an older woman. Japanese maybe? She looked dangerous, though. Cold. Percy ducked out of the way of her punch before throwing one of his own. The agent dodged and thrust her foot out, trying to trip Percy up. The son of Poseidon skipped out of the way.

Enough of this, he thought. Hand-to-hand was fine, but swordplay was his specialty. He swung his blade around, aiming for the woman's gun hand. Decommission, not decapitate, he thought. The agent caught the metal with the butt of her gun and knocked it aside. She threw another vicious kick at him, and Percy barely ducked out of the way.

Dang, Percy thought. She was good.

She threw three quick punches at his jaw, two of which he managed to evade. Stars exploded before his eyes, making him sway on his feet momentarily.

"May!" Someone screamed. "May! Finish him and get over here!" It was a man's voice coming through from her earpiece. As soon as Percy registered what he'd just said, he ignored the lights still flashing in his eyes and dropped to the dirt. Two gunshots rang out ear-piercingly loud right in front of him. Agent May—he assumed that was her name—leveled her gun at him, ready to shoot.

Well, great, he thought. He'd only been on the ground for a heartbeat before he rolled to the side, dropping his sword so he could use his good hand to grab her ankle and yank her to the ground. She lost her balance, turning the fall into a lethal weapon as her heavy boot slammed into Percy's chin. He blacked out for a split second before scrambling to his feet and picking up his sword again. His fingers had just brushed the hilt, however, when a bullet ripped through his leg.

Arrow :D