Riggs and Murtaugh have just arrived for their shift when they're summoned by their Captain. They saunter lazily in to his office, where Roger with a bit of a guilty conscience immediately starts defending them. "We didn't do anything this time."
Avery raises his eyebrows. "I'm sure the Committee of Good Neighborhood whose meeting you crashed – and I mean literarily crashed – into would disagree. But that's not what I called you in for. Actually I only wanted to talk to Riggs, but apparently you stick to him like flypaper."
Riggs turns in his seat to look at his partner. "He's right, you're a little clingy lately. You lonely? Trish still on that business trip?"
The other man nods pitiably. "And Riana has gone camping with her friends."
"Ah, cheer up, buddy. We can grab a beer later." Riggs claps him encouragingly on the shoulder.
Murtaugh seems happy at the prospect. "I'd like that. But I can't leave Harper alone, so we'll have to stay at my house. Hmm, I could cook something – maybe some steaks..."
Avery clears his throat.
Misinterpreting his superior's disapproving gaze, Riggs generously extends the invitation to him. "Don't worry, Cap. You can come, too."
"That's nice of you, but may I please continue? I mean, we are at work here." Having beer and steaks at Murtaugh's does sound nice, but he knows what Deputy Chief Santos would say to that. So he keeps a stern face and – it works: Though neither Riggs nor Murtaugh look contrite, they at least stop planning their man date. Once he's sure he has their undivided attention, Avery continues. "You probably heard about the string of robberies up in the Hills. Some very influential people –"
"You mean rich pricks," Riggs interjects.
"– put pressure on the Chief and he wants them stopped yesterday. But there aren't any real leads and zero evidence, so it's been decided to send someone in undercover. And that someone is going to be you, Riggs."
Murtaugh lets out a derisive snort. "You really want Riggs for undercover work? He's about as subtle as a brick."
The other man takes offense at that. "Hey, I can be subtle ...I just don't want to."
Before Murtaugh can respond and probably start a lengthy discussion, Avery steps in. "He doesn't need to be subtle, because he's perfect for this role." He turns to Riggs. "The security video we have showed four suspects, all masked. They were using military hand signals, so we think at least some of them are ex-military. And that's where you come in." Avery steeples his fingers together and points them at Riggs. "You're going in as a veteran who's down his luck and wants to blow off some steam."
"You're right, that's a perfect fit." Murtaugh laughs.
Riggs shoots him a dark look, but otherwise ignores his partner. "Going in where?"
"Some sort of underground fight club called the Wolves' Den – we believe the robbers are based there. You go in, have a look around and see if you can find anything. Murtaugh will be your contact as long as you're undercover. There's also a Henrietta Lange you need to see to get the outfit you need for undercover work."
Avery places his hands on the desk and leans forward to look them both in the eye. "This is serious, guys. If the owners were at home they were severely beaten. One victim fell into a coma, another one died of their injuries."
Both detectives nod, for once all playfulness gone.
Avery points at the door. "Go get them!"

As they stride out of the Captain's office, Murtaugh is mulling over something.
"I still don't see why they picked you for this mission."
"Face it, Rog. When it comes to fighting prowess or shooting skills, they'll always choose me over you. But if they need someone to play the bookkeeper or something, I'm sure you'll be the first they ask." Riggs nudges the older man playfully in the ribs.
"I've got a better theory."
"Is that so? Well, why don't you enlighten me."
"It's because they wanted someone who could fit in with these outlaws and I – unlike you – am settled and civilized. I play basketball after all." Murtaugh adds the last bit in an haughty tone.
"Since when is playing basketball the definition of being civilized?"
"Of course you don't understand that. You can't, because you're living on the beach like a feral–"
Riggs holds up a hand to interrupt his partner – he already knows that litany. "Yeah, yeah. I get it. I'm a sand hobo."
"That's right."
They keep walking in silence until Murtaugh suddenly stops and turns to Riggs.
"About that beer... You bringing Palmer too? Is she still in town? I haven't seen her around lately."
"Nah." At Roger's expectant look, he elaborates. "We, uh, broke up."
"You what? When?"
"A couple of days ago."
"And you didn't tell me?"
"No, because I didn't want to dump my shit on you."
"See, that's our problem right there, you never tell me anything. When it gets personal, you always clam up."
"I don't clam up." Riggs spreads his arms to show how open he is. "Okay, ask me anything."
"Alright, what's up with your hands lately? Your knuckles are always skinned. And..." He has been keeping quiet on this issue for a while now, waiting for an opportunity to present itself. Apparently this is it. "Our last case, the one with the singer. You looked ready to murder that Phil guy, just because he hit her a couple of times."
He says that last part purposely flippant, in hope of eliciting a reaction. He's definitely hit a nerve, because a muscle jumps in Riggs' cheek. Murtaugh holds his breath and waits for the inevitable explosion, but the younger man just plasters a forced smile, really more a grimace, on his face. "Ah, Rog, I'd love to talk to you about that, really go into detail, but I gotta go get changed."
He hurries off, gait stiff and faster than normal, and leaves a frustrated Roger behind.

Damn Roger and his prying questions. Riggs shakes his head. Murtaugh doesn't know what he's stirring up, things Riggs really doesn't want to think about. But he knows his partner, he's like a dog with a bone. Once he's sunk his teeth into an issue, he won't let go until he cracks it. It's what makes him a good cop. It also makes him a helluva pain in the ass sometimes, like right now. Maybe he should cancel their dinner plans, so as not to give Roger the opportunity to keep digging. But he doesn't like the thought of his partner rattling around in that big house all by himself when he's accustomed to pretty much constant company. Riggs is so distracted by these thoughts that he almost walks past his destination. He knocks on the door and enters, looking around. The room is full of clothes lying in stacks on various surfaces or hanging from clothes rails but there are no people, at least none he can see. So he calls out, "Hello? Anybody there?"
He hears her first, the clicking of heels on the floor. Then a diminutive woman steps into view from behind one of the clothes rails. "I'm right here, Mr. Riggs. There's no need to holler," she admonishes him.
He looks down at her. She looks a little like a librarian, all prim and proper and she is tiny. Even with heels she maybe comes up to his chest. "Mrs. Lange? I'm here for–"
"I know. And it's Miss Lange, but you can call me Hetty." She inspects his outfit with a critical eye. "I see you're already dressed for your mission."
Riggs gazes down on himself. He's in his usual getup, consisting of his favorite and by now only jacket, grey shirt, light blue jeans and trademark cowboy boots. "Uh, sure."
"The combat jacket with the bullet hole is a nice touch, but those boots..." She shakes her head in disapproval. "I believe I have a pair of army boots that are better suited." She bustles off and returns with the items in question, setting them down by his feet. "Here they are, nice and battered. And the trousers maybe a little darker." She wanders around behind him. Riggs jumps when her small hands tug at the back of his jeans. He quickly turns around to face her, taking a step back to put some distance between them. "Woah there, lady. We've just met."
Unabashed, she looks up at him. "You can relax, Mr. Riggs. I was only trying to get in your pants."
He stares at her, not sure he's heard right.
She gazes back calmly and adds, "... to determine your size."
Now he's sure he can see a playful light twinkling in her eyes.
He laughs, relieved. "Nice one."
"Thank you." She smiles slightly. "Now. I'll get you the jeans, you can try them on over there." She points to a curtained-off corner.

When Riggs emerges from Hetty's lair with his new-old attire it's still morning, so he's got time to kill until the club opens in the afternoon. He decides it's best to do paperwork, or rather pretend to do paperwork so he can ignore Roger. It's pretty uncomfortable – he can feel the other man staring at him over the desk, eyes boring into his skull. Finally it's time. He bids a hurried goodbye to Murtaugh and drives to the address Avery gave him.
The fight club is located in the gym of an abandoned high school with an empty swimming pool serving as the arena. The place is packed when he arrives and he automatically scans his surroundings, looking for threats and possible exits. He's just wishing his role wouldn't require of him to leave his gun in the truck, because he feels rather naked without it, when a man with a clipboard walks up to him.
"Hi, I'm Bob. New here?"
"Yeah."
"The fee is 20$ if you want to watch and 50$ if you want to fight."
"I have to pay to fight?"
"Yes, but if you win all fights, you get a percentage of this night's takings."
"Sounds like a deal. Sign me up." He pulls a couple of crumpled dollar notes out of his pocket.
Bob takes them and makes a sign on his clipboard. "Thanks. The rules are no shirt, no shoes, no weapons and only one climbs out of the pit."
"Simple and to the point, I like it. Who'll I be up against? Maybe that guy?" Riggs points his chin at a tall and rather arrogant-looking man with a pronounced burn scar on his cheek. He's staring intently at the fighters.
"No, not that one, he's a Warrior."
"A what?"
"A Warrior. Part of this group called the Blood'n'Guts Warriors. They run this place. They don't participate in the fights, but they watch and on occasion recruit the winners."
Interesting. That might just be what he's supposed to look for.
"Recruit them for what?" He tries to get more information, but Bob just shrugs.
"Don't know, I just manage the financial side." Both watch as one the fighters bounces the other off the pool wall where he lands in a heap on the floor. "That was quick. How disappointing. Well, you can have a go now, if you're ready."
"I was born ready." Riggs takes off his shirt and shoes and climbs into the pit for his first fight.
He wants to make an impression, but it's not easy since the first few men that come at him are almost ridiculously slow. In the beginning he goes with the basic five-second knockout – a flurry of blows, then the fight is over. But that's a bit boring. So he starts to draw the fights out, lets the other guy land a couple of hits to keep their spirit up and relishes the pain it brings. When his opponent is beginning to tire, he moves in for the finishing blow. Some guys are better and the fights more interesting, but in the end none of them are trained killers like he is, so the outcome is still the same. At the end of the night he goes to collect his take, smirking as he feels the Warrior's eyes on him. He's starting to like this mission.

This goes on for a couple of weeks. He'd show up at irregular intervals – not too often to avoid being suspicious –, win every fight, collect his money and leave. Being undercover, he isn't allowed to come to the office and it leaves him too much time to think. Which is exactly what he has been trying to avoid, first by working long hours, then by diving headfirst into the relationship with Palmer. Now those options have been taken from him, so he tries to occupy himself by exercising and practicing his shooting. He has this vague notion that as long as he keeps moving, he can maybe outrun the memories.
'Running again, little rabbit? You always were a coward.'
Unbidden, the spiteful voice of his father echoes through his brain. He flinches, feeling the old emotions flooding him – a swirling black vortex of hate, fear, anger and guilt threatening to swallow him whole. No. He clenches his fists so tightly it hurts, detesting that after all these years the man still has such power over him. He holds on to the anger, as that's the emotion most easily dealt with and slams his fist against the wall, leaving his trailer with a nice new dent and once again ripping open the skin on his knuckles. But it's not enough. Panting, he decides to fuck inconspicuousness and go to the Wolves' Den right now. After all, there's nothing like a fight to release all that pent-up emotion. He grabs his car keys and is on the way out as his phone rings. It's Murtaugh. Riggs internally debates not picking up and just going straight to the Den, but he still has a job to do and he isn't one to shirk his duties. He accepts the call and listens to his partner informing him of the address of today's meeting location, as they vary places to, once again, avoid being conspicuous. This time it's a bar where they'll sit next to another at the counter and pretend not to know each other. Riggs wants to get this over quick and probably broke some speed records driving over, so Roger isn't there yet. Impatiently waiting for his partner to show up, he bounces his leg and drums his fingers on the counter. The bartender and other patrons give him a wide berth. He doesn't blame them, he knows he looks every bit the unstable vet he's supposed to portray. Still, it kind of stings. His mood isn't improved either when Roger finally slides onto the stool next to him, because the first thing he says is, "You've got blood on your hand." Then, noticing the waves of nervous energy radiating off Riggs, he adds. "And you're looking kind of antsy. You alright?"
"I'm fine," Riggs snaps, feeling immediately guilty at his partner's hurt expression. After all, he knows Roger means well. But he's fed up with his constant questions, he wishes the man would just let him be. Abruptly, he hops down from the bar stool.
"I gotta go."
Murtaugh can only shake his head.

Later that night, after some much needed cathartic release, he feels better and his head is wonderfully empty. He once again walks into Bob's office to get his winnings, but instead of forking over the cash, he invites Riggs to sit down a minute.
Bob consults his trusty clipboard, thoughtfully scratching his head. "I see you've won every night so far. While I admire your talent, it's bad for business –the outcome is just too predictable. There's one guy I'd like to pitch you against. Biker dude named Stark or something." Riggs has seen him around, dressed in black leather and all scarred up. Riggs himself has his fair share of scars, but this dude looks like someone put him headfirst into a wood chipper. And he holds himself like a born fighter, easily balanced on the balls of his feet. He wouldn't mind going against that guy, it might finally make an interesting fight.
"Unfortunately he's not a regular, and I don't know when he'll next come in. But I've got a different proposal for you, if you'd like to hear it."
"Sure."
But instead of speaking, Bob motions to the door. It opens to admit four guys, who aggressively surround Riggs.
"An orgy? That's very flattering, but I'm really not that kind of man." He turns to look back to Bob, but the man has vanished. So that's how it is. He rolls his shoulders and brings up his fists, going into combat stance. "Well, bring it on."
And they do.