Disclaimer: It's not mine. The world and characters are Marvel's.

Spoilers for Infinity War.

Author's note: I'm not going to lie to you: this is going to be a little weird. This story will jump around in chronology a little. It's not going to be straightforward. It doesn't focus on how the Avengers defeat Thanos, but rather the aftermath. I'll tell you up front there will be plot points that won't make sense at first. If you choose to bear with me, I hope your patience will be rewarded with a good story.

Rated T for strong language and evil.

Heartstring Theory

Chapter 1: The Candle

"First Fig"

My candle burns at both ends;
It will not last the night;
But ah, my foes, and oh, my friends—
It gives a lovely light!

~Edna St. Vincent Millay

The image of the tentacled skull had a metal panel embedded between its eyes.

"We were right; this is a HYDRA base," Natasha reported.

Sam stepped beside her. "Man, that is a lot of pent-up anger."

"We've got casualties here," Steve reported over the comm.

"Dead?" Natasha asked.

"Doesn't look like it. Injured, catatonic."

She turned and made her way down a dark corridor. Dark because the light fixture was lying on the floor in a scattered mess of metal and glass. There were people in the hall, huddled in fetal positions, staring off into nothingness, mumbling to themselves.

She knew what they were going through.

"Remember, if you locate her, do not engage. We need to talk her into coming quietly," Tony said.

"It's not like we haven't fought her before," Spiderman replied.

"You haven't fought her like this," Natasha countered. "It's not just that she was holding back at Leipzig Airport. She stopped using her mental powers when she joined the Avengers. We all agreed they were too damaging. She chose to limit herself. She's not doing that anymore."

The next voice over the comm was Hope van Dyne. "There's so much...wanton destruction here. She's just breaking everything."

Natasha and Sam entered a room that had clearly been some kind of lab. There were three bodies in the room. A woman and young man had been shot in the head, another man had been twisted and torn apart, much like almost every item of furniture in sight.

"Nat, we've got a live one," Sam said, looking under a table.

She stooped down and found a middle-aged man, in the same uniform as the rest of the HYDRA agents, cowering as far against the wall as he could get.

"Where did she go?" she asked.

He shook his head, not looking at them.

"We're not going to hurt you," Sam said. "I mean, we are going to arrest you, but you'll be safe."

He still didn't say anything. He was clutching a photograph of a young family.

Natasha glanced at Sam. "I don't think he's going anywhere. Let's keep looking."

"I've got someone on thermal in the sub-basement," Rhodes reported. "It could be her."

"Is anyone on that level?" Steve asked.

"I am. Kind of," Scott Lang answered. "Where am I looking?"

"A hallway, north side. Heading east."

Natasha and Sam sprinted down the hall to an elevator. Sam blew the door in. "Hold on."

She grabbed onto him and they dove down the elevator shaft. Near the bottom, Sam shot another missile to blow open the door. He made a sharp turn and flew into the opening beyond. He landed, and Natasha hopped off.

This level was dimly illuminated with emergency lights. There were a few more HYDRA guards down here. Some were dead, though the lack of external injuries indicated they'd poisoned themselves. Those who were alive were staring, unresponsive to their presence, lost in nightmares inside their own heads.

"When we find her, maybe you should talk to her first," Natasha said. "She likes you more."

"You scared?" he asked, trying to make a joke.

A denial sprang to her lips, but she discarded it in favor of the truth. "Yeah."

Guns lay in twisted heaps, there were knives buried to the hilt in the metal walls.

"This is more destructive than her last targets," Sam noted.

"Those weren't HYDRA. This is the organization that made her what she is. It makes sense she'd hold them responsible for ruining her life."

Scott's voice crackled over the comm. "I've got visual. It's her."

"Do not engage," Steve said. "Stay back until Clint, Nat, Sam, or I get there."

"Copy. She hasn't seen me. Wait...she's looking at me. What do I do?"

"Pull back. Sam and I are almost there," Natasha answered as they sprinted down the corridor.

"She just...shit. She just tore open a hole in the wall!"

Natasha and Sam rounded a corner. They didn't see Scott, who was probably almost microscopic somewhere. They did see the gaping hole in the wall, metal peeled back, and a kaleidoscopic dance of red light and the clang of metal coming from it.

She held Sam back for a few moments. When the light stopped, she ran forward, Sam right next to her.

"Wanda?" Sam called. "Wanda, it's us."

They stopped at the hole. The room beyond was an armory, the weapons practically shredded. Wanda stood among them. She wore pure black. Her hair was tightly braided and almost bizarrely unruffled, considering she'd just rampaged her way through a HYDRA base.

She looked back at them. It was the first time they had seen her since Thanos. She looked pale and thin, and what was in her eyes was hard to read.

"Wanda, we need to talk to you," Natasha said.

She shook her head. Just barely. She spread her arms open and her fingers wide. Red light eminated from her, spreading out in tendrils into a sphere. It didn't look like lightning, more like veins, or tree roots. Spreading ever wider.

"What's she doing?" Sam whispered.

"I don't know. Get back."

They backed away, toward the far side of the hall. They saw Wanda twist one hand, and a mass of concrete, metal, rock, and dirt lifted from the floor. She tossed it aside and jumped down the hole she'd just created, followed by a bright, solid flash of red.

And then darkness.

When their eyes adjusted, Sam and Natasha entered the armory and looked down the hole. Sam turned on a flashlight.

"Where did she go?" he asked.

It was simply a hole in the ground. There were no tunnels, no caves, no way out at all. But it was completely empty.