Just like Virgil said, they were able to pick up the Courser's signal through a classical music station on the Pip-boy's radio. It was nearly nightfall by the time they tracked the steady beep, beep, beep to Greenetech Genetics, a huge seafoam-green monstrosity placed about a mile to the east of the C.I.T.

The coppery scent of blood was heavy when they stepped through the doors. Fresh bodies were littered everywhere; they were all Gunners, judging by all the military fatigues and assault rifles.

"Holy shit," Hancock said as they stepped gingerly over the corpses and puddles of blood. "These guys were fuckin' slaughtered."

"And one synth did all this?" Rose murmured to herself.

Gunners were no joke, as far as enemies went… they were the most highly skilled mercenary group in the entire Commonwealth. Even raider gangs had a tendency to avoid the places where Gunners had staked their claim. For one synth, even one programmed to excel in combat, to take out this many of them… it was unnerving.

Rose's head snapped up at the sound of retching. Cara was standing in a corner by the door, doubled over and gagging. Ichabod was huddled by her feet and cheerfully lapping up blood from the floor.

Rose's heart sank. She moved over to her sister to put a hand on her back. Ichabod looked up at her curiously, and Dogmeat issued a light growl at him at though warning him to behave.

"You don't have to keep going," she said gently. "It's not going to get easier further in."

"No." Cara shook her head and wiped at her mouth. "I'm okay. It's just… I wasn't expecting this, is all. It's kind of a lot to take in all at once."

Rose heard a light rattling sound, and glanced over to see Hancock holding a small green bottle in his hand. He gave her a pointed expression and she nodded.

"Hey kid, why don't you take one of these?" he asked, tossing the bottle into Cara's hands. "Had some left over from my stash in Goodneighbor. Oughta settle your stomach and dull the, uh, horror, a little bit."

"Day-Tripper?" Cara asked as her eyes skimmed over the label. "I know this. It gets passed around at the frat parties a lot." She frowned. "Or, it used to get passed around." She held it back out to him. "No thanks. I probably wouldn't be able to keep it in my stomach long enough to take effect anyway."

He took it back with a shrug. "Suit yourself, sister. But if you find yourself cravin' a fix, you just let me know."

"I will." She took her 10mm out of her leather bag and checked the magazine the way Rose had taught her, her hands just a little shaky. "So we good to go?"

Rose brushed Cara's hair back and hummed an affirmation. "Yes. But let's get a few things straight before we go any further."

"I already know-"

"First: I am the boss right now," Rose said, speaking over her. Her posture had straightened and her voice became commanding, in the same way it was when she was organizing the minutemen. "If I tell you to do something- even if that's to run and leave me behind- you fucking do it, no questions asked. This isn't screwing around with ferals or molerats or giant bugs… these people are trained killers. They are not going to be easily distracted, they are not likely to miss, and they aren't going to show you mercy. Second: you are to stay behind me and Hancock at all times unless I tell you otherwise."

Cara started to argue, but Hancock cut her off. "Trust me, kid. You don't wanna get in between your sister and someone who's pissed her off."

"Keep behind cover and only shoot if you need to," Rose continued. "Don't wait on using stimpaks if you get hit… you can bleed out much more quickly than you think. And if you can't use one yourself, yell out and one of us will do it for you."

By now Cara was extremely pale, but she kept her chin held high. "Okay. Anything else?"

Rose dropped her eyes to her shotgun, loading it and chambering a round a little more aggressively than was necessary. "Yeah. If you get yourself hurt, I'm going to kill you."

The Courser may have made short work of the Gunners in the front, but the rest of their party was very much alive… and very pissed off. Luckily, they were so distracted by trying to bust into the elevator for the top floor that they didn't notice another group had come up behind them until about half of them were already dead.

Cara crouched obediently out in the hallway as Rose and Hancock picked off the remaining Gunners one by one. Rose tried not to feel her gaze as her shotgun blew fist-sized holes through the mercs' armor, or as she commanded Dogmeat to rip into the men her shots had crippled.

A spike of fear went through her as they ascended to the top levels of Greenetech. Rose kept telling herself that the Courser was just another faceless monster, repeating it over and over in her head like a mantra, but truthfully she was scared. The Institute didn't play around; it would be a miracle if they all walked away from this unscathed.

They entered a large, multi-level room that had a staircase winding up several floors over their heads. It was mostly empty, but as they neared the topmost floor voices began to echo down and become more clear.

"I'm telling the truth, I don't know the password!" This first voice was high-pitched, panicked. A captive Gunner?

"No, I don't think you are." The second voice was cool, emotionless, and dispassionate. It had to be the Courser.

"No, please, you don't have to do this-!"

The ping of a laser rifle echoed down the staircase. Rose felt Cara shrink back against her at the sound. Even Ichabod flinched, pulling himself up her like a cat and ducking into her arms… though Rose guessed he was just bothered by the sound.

"All he had to do was tell me the password. Now, are you going to cooperate?"

Rose felt her jaw clench. This thing had subdued a bunch of professional mercenaries like it was nothing, and yet here she was. She was a damn housecat facing down a wolf. She palmed a hit of Psycho from her pack and slammed it into her thigh, doubling over from the effort it took not to scream out as the adrenaline-fueled drug torched through her veins. She could feel Hancock's hand on her back, steadying her, and Cara's ever-present stare… the latter would've made her cheeks burn if she weren't so suddenly overcome by the need to kill everything in the room.

"Stay down here," Rose hissed to Cara past a clenched jaw.

"Not a cha-"

"Do not argue with me." Her voice came out in a low, deadly growl, just quiet enough to avoid carrying up to the next floor. "You stay down here and wait, and if we go down, you fucking run. Remember what I told you."

"I'm not leaving you."

On the level above them, the sounds of the remaining Gunners pleading for their lives grew steadily louder as the Courser started to lose patience. Cara looked up towards them, with what little blood left in her face draining away at their terrified voices.

Rose made eye contact with Hancock briefly. His jaw tightened unhappily, and gripped Cara's arms like he was steadying her, careful to keep his hands out of reach of Ichabod's teeth.

"Hey, what are you-?"

While her head was turned away, Rose brought up the butt of her shotgun and swiftly brought it down on the back of her sister's head. Cara went limp instantly, eyes rolling back, but Hancock kept her weight supported and gently eased her down onto the steps. Ichabod sniffed at her face curiously and squeaked, as though not understanding why she wasn't moving. Dogmeat whined and licked Cara's face.

"She's gonna hate you for that," Hancock muttered.

Rose took a deep breath, pushing the guilt to the back of her mind to deal with later. "At least she'll be alive to hate me."

She crouched down for a quick instant to pump half a stimpak into Cara's biscep; that would take care of any damage and any pain by the time she woke up.

"If you start taking bites out my sister, I'll turn you into a pair of boots," she warned Ichabod. The young deathclaw spared her a bored look, curled up on Cara's stomach like a scaly cat, and closed his eyes. Evidently the excitement of battling a miniature army of Gunners had tuckered him out.

Satisfied that her sister was out of harm's way- or at least as much so as possible- Rose motioned to Dogmeat and Hancock to continue up the stairs.

"I'm going to get in there, it's just a matter of time," the Courser was saying. "Tell me the password."

They edged out onto the landing. The Courser had four Gunners tied up in front of a room locked down with steel gates; one of them was lying prone in a puddle of blood.

"Look, I already told you I don't have it!" one of the Gunners pleaded. "I'll help you find a way in, but listen, we took the girl fair and square-"

The Courser's eyes snapped up to Rose. "You've been following me," he said matter-of-factly, shifting the barrel of his rifle towards her chest. "Are you after the synth?"

"In a matter of speaking," she replied, sighting down her shotgun.

"Ah, so you're here for me, then." His voice was maddeningly calm, like they were having a chat over tea. "No matter. You'll die like the rest of them."

He fired, but Rose had anticipated it; she rolled forward towards the Courser and fired off two shots into his chest. He must have been wearing some kind of armor underneath the black leather coat he wore, because he took the hits and stayed standing.

Her intention was to stay as close to the Courser as possible; his rifle was better at range, which gave her the advantage if she stayed close enough to keep him from being able to aim properly. But a second later he vanished out of view.

Hancock swore. "Did he just…?"

"Invisible!" Rose shouted back.

She could see a faint blurriness as the Courser tried to create some distance between them. She did the only thing she could think of, and lunged forward to try to grab onto him. She managed to catch what she was pretty certain was his arm, but the Courser knocked her shotgun down when she tried to fire. She felt his hand lock around her wrist- stronger than a steel vise- and screamed when he twisted it violently to the side. Her wrist broke like he was snapping a pencil. She dropped to her knees as the Courser continued to keep pressure on the break, sending blinding pain racing through her entire arm. She felt the heat of the rifle barrel against her temple, but the pain was so great she could barely breathe, let alone pull free.

"Drop down!"

Rose forced herself to go limp at the sound of Hancock's warning. Another strangled scream erupted from her throat as her weight pulled her hand roughly from the Courser's grip. A second later Hancock fired in the Courser's general direction, and from the sound of it managed to hit his target. Rose flinched as hot blood splattered on her head and back.

The Courser flickered back into view; his Stealth Boy had been damaged by the attack. He was bloodied, but still lethal; he rounded on Hancock as he scrambled to reload. Dogmeat slipped past him and sank his teeth into the Courser's arm, shaking his head violently from side to side. The Courser was pulled down by his weight and tried to yank Dogmeat off, but his jaws were locked deeply into his flesh.

Hancock was still reloading. The Courser finally tore Dogmeat off, tossing the shepherd against the staircase railing. He took aim for Hancock's chest; Rose forced herself to her feet and rammed into him from the back with her shoulder. The two of them tumbled forward as she knocked him off balance. She tried to keep leverage, but with one useless arm the Courser easily overpowered her. She felt his fingers lock around her throat and he slammed her against the ground; stars exploded in front of her eyes and then immediately began to turn black as he tightened his hand around her windpipe, choking off her air. She scrabbled at the back of his hand with her nails, but he used his free hand to slam the butt of his rifle down on her injured forearm; she couldn't scream, but the pain was so intense that she nearly blacked out.

"Bad move!" Hancock snarled. He couldn't fire his double-barrel without risking Rose, so he pulled out his knife and swiped at the Courser's neck. He managed to cut a deep gash into the side of the assasin's throat, but the damn thing still wouldn't go down. He released Rose and brought his rifle up with unnatural quickness, forcing Hancock to dive behind the giant metal grates that rose up through the center of the floor.

Rose drew in a couple of ragged breaths and reached down by her side, wrapping her fingers around the grip of her pistol. The Courser was still crouched above her; he was busy raining fire towards Hancock to keep him pinned down. He appeared to be weakening from the blood flowing out of his neck, though; his shots were shaky and inaccurate.

By then Dogmeat had recovered. He appeared over the Courser's shoulder and bit down on the space between his neck and collarbone. His weight pulled the Courser backwards, and Rose saw her opening. She brought her pistol up in her left hand and jammed the barrel underneath the Courser's chin, firing off the entire magazine in the space of about two seconds. The Courser's eyes went vacant, and after about a heartbeat he slowly fell backwards and was still.

There were a few moments of motionlessness while they waited to make certain the Courser was absolutely dead. But he didn't get up again, and Rose found no pulse when she pressed the fingers of her good hand against his neck.

"Jesus Christ," one of the Gunners said in awe. He and his remaining buddies were huddled up in the corner, still bound. "That thing took out like twenty of our guys… and you two put it down in three minutes."

"It's an off day," Rose said sarcastically. She experimentally tried to flex her fingers and hissed. Her entire arm was on fire; she didn't even want to look at it.

"Lemme see that," Hancock said. He took her hand extremely gently, but even that light touch was enough to Rose bite back a scream.

"That's gonna need to be reset," he observed grimly. "It'll be a day or two before it heals too, even with stimpaks."

"I'll worry about it in a minute." She marked the spreading bloodstains on his shoulder and calf, frowning. "You alright?"

"Bumps and bruises, love. Courser caught me with a couple of stray bursts. Nothing a stimpak and a few hits of Jet won't fix."

Dogmeat whined, and she looked over to where he was staring pointedly back down the stairs. "Will you go check on Cara? I'm going to dig out this damn chip."

Luckily, the courser chip wasn't hard to find. Rose could feel the outline attached to the Courser's skull, right at the base of his head. It took a little work to pry it off one-handed, but she managed. Then she walked over to the locked door, sparing a withering glance for the captive Gunners.

"We don't know the password!" one of them piped up immediately. "Please don't kill us!"

"I figured as much." She tapped the keyboard of the terminal… hacking was a lot more difficult one-handed, and the pain in her wrist made her focus fuzzy. "And I'm not going to kill you, unless you try something stupid. I've had my fill of bloodshed for the day."

"You knocked me out?!"

Cara's shrill, angry voice drilled right into Rose's brain; she winced, noting that she could add a headache onto her list of injuries.

"It was that or drug you, and I figured you'd be happier without a Med-X hangover."

Rose tried to continue hacking the terminal, but Cara reached her and shoved her back against the door.

"What the hell is wrong with you, Rose?!"

"She probably saved your life, kid," Hancock said, coming up behind her. "That Courser took more hits than a mirelurk queen to put down."

"And you broke your wrist?" Cara demanded, when she spotted the heavy bruising already spreading around Rose's limp arm.

"Technically the Courser broke it. But yes."

She huffed. "Well, you deserve it. I can't believe you actually fucking hit me, Rose."

"You weren't going to listen to me anyway!"

Another one of the Gunners was watching them in confusion. "Are you two really arguing about-"

"Remember what I said about doing stupid things?" Rose growled at him, and he immediately shut up.

"You could've been killed, Rose." Cara was still clearly angry, but her aggression was subsiding the more she took in her sister's haggard and bloodstained appearance.

"And you would have been killed," she replied, suddenly exhausted. "Cara, that thing very nearly killed Hancock and me both. It is through sheer luck that we're both still standing. I did what I had to do to protect you, and I'm not going to apologize for it. You probably don't even have so much as a headache after that stimpak I gave you."

"That's not the point!"

Rose rolled her eyes. "Fine. Then we'll talk about your point later when I don't have a shattered wrist to distract me."

She finished hacking the terminal by way of ending the argument. Cara was glowering, but her entire posture changed when the doors slid open and she saw the young woman huddled in the back of the room, wide-eyed and shaking like a leaf.

"Hey, are you alright?"

The girl looked at her warily. "Depends… you want to sell me off too?"

Cara shook her head. "Nah, we're the good guys. Even though it might not look that way," she added, glancing sidelong at the bodies and blood on the floor behind them. She held out a hand to the girl and smiled. "You're safe now, I promise."

The girl studied her carefully before accepting Cara's hand and edging outside. The Gunners began to fidget and make noises of protest.

"Hey, that's our payday you've got there!"

Rose whipped out her pistol again and pointed it right at the complainer's head. "You three really have a deathwish today, don't you?"

"Don't need to bother wastin' the ammo," Hancock said darkly, pulling his knife out and twirling it demonstratively.

"Rose, they're tied up and unarmed!" Cara objected, stepping in front to block her shot. "You're not really going to kill them, are you?"

"You want to risk them coming back to kidnap her again?" Rose asked, jerking her head towards the synth. "Or taking someone else?"

"Some people are just better off dead, sister," Hancock added.

"You'd be murdering them in cold blood; that's not right and you know it."

"Don't spill any more blood on my account," the synth said in agreement, even though she was staring at the Gunners with a strong sense of hatred. "I'll be alright on my own. If I can't learn to fend for myself out here, I'll never be able to survive."

Rose considered them for a moment, and then lowered her gun with a sigh. "Fine." She turned to the Gunners. "But if I see any of you in the Commonwealth again, I'll shoot to kill… and I don't miss often. Got it?"

The three of them nodded in unison, afraid to speak lest they ignite her ire once again. Rose's wrist was shrieking in pain, so she tapped her pocket to make certain she still had the courser chip, and motioned for them all to leave.

"Let's get out of here before I change my mind."