She knew something was off the moment Garrus turned to greet her. He stood straight and tense, his shoulders hunched like a man a breath away from putting up his fists. In the half-dark of the battery, his face was shadowed; all she could see was the glow of his eyepiece and the ragged edge of his right mandible.

"Shepard. I was about to send you a message." His voice was clear, but there was a buzzing tone underneath his words that had her on alert.

"What's wrong?"

"I got a tip on Sidonis."

She stepped fully into the battery, feeling her lips thin to an angry slash. The door hissed shut behind her, and she leaned up against the crates to the side, watching Garrus.

"Tell me."

"There's a specialist on the Citadel. Fade. Helps people disappear."

"And you think Sidonis made use of his services?"

Garrus had settled into a pace across the length of the battery. Two steps up and two steps back. "He was seen in his company."

She drew in a deep breath. "So. What's the plan?"

He stopped and turned to face her again. "He owes me ten lives. I plan to collect." His voice was clear, preternaturally calm and certain.

"You sure about that?" she asked quietly.

He glanced briefly away. "I know you don't like it, Shepard. I'll take care of it on my own if you want to stay out of it. But I'd like your help."

She got the feeling that there was something else going on here, maybe something to do with Hierarchy culture, or something peculiar to Garrus' background in particular. The whole thing made her uneasy - she'd never seen Garrus agitated like this before, and it reminded her sharply that he'd spent two long years fighting a private war on Omega. She hadn't been there, couldn't offer a judgment on Sidonis' guilt or say whether Garrus was right about this. But it was a hell of a lot of trust he was putting in her. Like hell she'd let him do this alone.

"You've got it," she said, firmly.

They found the trail of Fade - Harkin - easily enough. Garrus was a live wire at her side, humming with suppressed energy. He was sharp and on-alert, and kept his voice level. But his subtones backed every word like thunder heard over a distance, and the crowds on the Citadel carved out a wide space around him. Shepard set her jaw and watched him, waiting for any sign of a break in his composure. She'd commanded men in the past who'd carried that kind of intensity, and she knew how to talk them down or push them back. Garrus might be right about Sidonis, might be willing to pay whatever the cost was to put that particular ghost to rest. But she was damned if she'd let him risk Citadel murder charges on some nameless thug.

It was not until they were face-to-face with Harkin that she realized her mistake. Garrus was in no danger of losing his temper. On the contrary, he was frighteningly in control of himself.

She'd fought beside Garrus dozens of times. She knew he was capable of violence, like any other soldier. But she'd never watched him apply it with such ruthless calculation. He hurt Harkin precisely and deliberately - not enough to do permanent damage, but plenty to make him follow orders.

She knew what went into that kind of cold anger, and she didn't like seeing it on him.

When he took aim to cripple Harkin, she grabbed his arm, sent the shot wide. He tilted his head, so that he could look at her while still keeping an eye on their prisoner. She stared back.

"He's not going to get away. C-Sec's on their way. There's no need to shoot him."

He held her gaze for a half a second before holstering the pistol. She half-turned, and before she could react, he lunged forward, snake-quick, and landed a blow that sent Harkin reeling back to slump against the wall, dazed.

He stared her down. "I didn't shoot him."

She sent him a warning glare, but bit down on her immediate reaction. They were on a schedule, and couldn't afford an argument. "Let's get out of here."

The ride to the meeting spot was tense and quiet. At last, the cab landed, and she turned to look at Garrus. He was watching out the window, scanning the street.

"You all right?"

He turned a look on her. It was a dumb question, and they both knew it.

"You didn't go easy on Harkin back there," she said by way on explanation.

"He deserved a lot more than that."

"He was right, though. It's not like you."

He let out a slow hiss through his teeth. "What do you want from me, Shepard?" He sounded tired. Older than he was.

Impulsively, she gripped his arm, forced him to meet her eyes. "I want to be sure you're sure about this. You don't have to go through with it."

"If I don't take care of it, who will? No one else knows what Sidonis did. No one else cares about what happens on Omega. Ten good men died long, ugly deaths for him. He can't be allowed to go unpunished for that." There was a barely audible tremor in his voice, and his subtones hummed under his words like a hornets' nest.

She found no ready answer to that, and he pulled his arm out of her grasp, looking back towards the boulevard.

"I need to set up. I'll have a clear shot from over here." He swung back around to look at her. "Get him out in the open and keep him talking."

He got out of the cab, and she watched him go, heading for the shadows of a maintenance ladder.

Sidonis was easy to spot, even without Garrus' pointing him out. A thin man, hunched in on himself on a bench to the side of the main thoroughfare, his hands clenching and loosening around each other rhythmically. Even after long association with Garrus, she still found strange turians difficult to read, but she thought this one looked ill, his eyes sunken back in their sockets, the skin around them pale.

"Lantar Sidonis?"

He started, came off the bench to meet her.

"Don't say that name aloud!" His voice was younger than she'd expected.

Garrus' voice came in over her earpiece, thin and tense. "You're in my shot. Move to the side."

She took a long look at Sidonis, and for a moment teetered on the brink before coming to a decision.

Damn him. And damn me.

"Listen. I want to help you. I'm a friend of Garrus'."

She watched Sidonis' mandibles clamp spasmodically to his face. "Is this some kind of joke?" he asked weakly, even as Garrus' voice hissed furiously into her ear.

"Damn it, Shepard. If he moves, I'm taking the shot." Almost, she could feel his crosshairs hot on the back of her head.

"Screw this," said Sidonis, his voice fraying. "I'm not sticking around to find out."

He made to back away, and she grabbed his arm and jerked him back towards her. "Don't move. Right now, I'm the only thing between you and a hole in the head."

He stared at her for a moment, wild-eyed. "Fuck," he said, in a very small voice. "Look, I didn't want to do it. I didn't have a choice!"

"Everyone has a choice," ground out Garrus' voice.

"They got me," said Sidonis. "Threatened to kill me. What was I supposed to do?" He was agitated now, moving nervously back and forth. She kept pace with him, keeping herself in Garrus' sights.

"Let me take the shot, Shepard. He's a damned coward."

"You were trying to save yourself?"

Sidonis seemed to deflate at the question, leaning heavily against the safety rail at the edge of the street. One hand covered his eyes, resting there for a moment before he lowered it. "Yeah," he said bitterly, "I saved myself. And the rest of them died because of me. I know what I did." His subtones were a low, whining thrum at the edge of her hearing. "I'm already a dead man. Some days, I think it would be a relief for it just to be over."

"Just give me the chance," snapped Garrus.

She took another long look at Sidonis, and hoped like hell she was making the right decision.

"You've got to let it go, Garrus."

"Like hell I will," he said, but his voice was thin, more grieving than angry.

She took a chance, turned sideways to let him get a clear view of Sidonis, who had not moved from his place slumped at the rail. "Come on. Look at him. There's nothing left to kill."

There was a heavy silence over the comm as the seconds ticked by, and then Garrus spoke again, his voice thick. "My men. They deserved better."

Sidonis spoke up again. "Tell Garrus…" He trailed off into discordant subtones. "I guess there's nothing I can say." He sounded defeated. Lost. He still hadn't moved.

After a moment, she heard a breath in her ear.

"Just…go. Tell him to go."

She turned to face Sidonis again. "He's letting you go."

He blinked up at her, and for a moment, she thought he was on the brink of arguing, but at last he exhaled and straightened up, looked up toward the dark of the maintenance tunnels, where Garrus waited out of sight. He stood still for a second, and she thought he would say something more, but he only shook his head and murmured, "Thanks."

She did not think he was honestly grateful.

She met Garrus back at the cab. The energy seemed to have bled out of him, his shoulders slumped and his hands loosely curled at his sides. Before she could say anything, he skewered her with a look.

"I know you want to talk about this. But I don't." He glanced away. "Not yet."

She let out a breath. "All right."