A/N: Just how much do we really know about Detective Donald Flack Jr.? Does he have any siblings? Well, I decided to try and answer that question. Ladies and gentlemen, please meet Madigan Flack. R and R so I know it's worth continuing!

Chapter 1

When Detective Mac Taylor came in to the precinct, it was late at night and he was tired and looking forward to finishing his work so he could get out of there. Doctor Peyton Driscoll, the medical examiner he was seeing these days, had offered to make dinner for him and he'd accepted. In the reception area, he spotted what looked like a young male fast asleep on his side on the visitor's bench.

"Who's that?" Mac asked the officer on duty at the desk.

"I don't know, but he's been there for the last couple of hours. Finally fell asleep about an hour ago. The last officer on duty says he's been waiting for Detective Flack but wouldn't give a name, just said the detective knew him," the officer replied, shrugging.

Mac nodded. "Guess I'd better wake him; Flack was right behind me."

He went over to the sleeper, set down his crime scene gear, and gently put a hand on his shoulder, noting that he was more of a she, based on the facial characters. She just happened to have very short, dark brown hair and wearing a large, over-sized jacket, jeans, and boots. That was the last thing he clearly remembered. The next thing he knew, he found himself flat on his back, the female clearly awake with his dress shirt in her fist, kneeling over him, and her other fist drawn back to hit him. The look on her face was a mixture of rage and desperation. Before she could hit him, Flack appeared behind her and grabbed her wrist, wrapping his other arm around her neck and lifting her off her feet and away from him.

"Oh no you don't!" Flack yelled, struggling to restrain his captive as she fought.

She cried out, struggling, and Mac noted her yelling seemed to be more of one of pain and fear than one of rage. She also seemed to be trying to arch away from Flack. Suddenly she sighed and went limp as she slid into unconsciousness.

"What the hell?" Flack asked as he lowered his limp captive to the floor and Mac got off the floor, Stella helping him. She had arrived just seconds after Flack. "Somebody call an ambulance!" Then his eyes went wide as he saw the face of the woman, who was clearly in her early to mid twenties. "Oh my god," he breathed, tenderly touching her face, as if he couldn't quite believe what he was seeing. "Is Sheldon still around?" he asked, quickly checking her vitals; there was a steady heartbeat and regular breathing, indicating she was reasonably okay. Stella nodded, getting out her cell phone to call the former-M.E.-turned-CSI who also happened to be a doctor. He turned his attention back to the woman in his arms. "Oh Maddy, where've you been, kiddo?" he asked her softly, worry etched on his face as he gently brushed her hair away from her face.

"Flack, do you know her?" Mac asked, concerned.

Flack looked up at him and confessed, "This Madigan, my baby sister. I haven't seen her in almost six years."

"I didn't know you had a sister," Stella said, joining them.

"There's a lot of things you don't know about me," Flack quipped. He spotted something on her left wrist and lifted her hand up. It was a silver men's watch with the NYPD logo on the watch face. It looked worn but cared for. "Stella, could you check the back of that watch for me? If that's what I think it is, there should be something engraved on it."

Stella did as asked, putting gloves on, carefully removing the watch, and turning it over. "Donald, congratulations on graduating from the police academy," she read aloud. "There's a date here, dated about ten years ago."

Flack smiled and looked down at the still unconscious Madigan. "You didn't pawn that thing after all, did you, Maddy?" he asked her softly, just as Sheldon Hawkes came up to them, First Aid kit in hand and concern on his face.

"What happened?" Sheldon asked, snapping on gloves and quickly checking Madigan's vitals.

"I don't know. I saw her attack Mac and was about to take a punch at him when I grabbed her," Flack said. "She started screaming like she was in pain and then she went out."

Sheldon nodded and said, "She appears to be okay, just unconscious."

"I noticed she seemed to be trying to arch away from him. Could she possibly have an injury on her back?" Mac asked.

"It's possible. Help me get this jacket off her so we can have a look. Has anyone called an ambulance?" Sheldon asked.

"They're on their way," the on-duty desk officer said, joining them.

Mac, Flack, and Sheldon carefully sat Madigan up and removed her jacket. "That is not a good sign," Sheldon said as they stared at the blood that was seeping through the back of her t-shirt. "We need to cut this off. Let's get her into the recovery position."

They got Madigan on her back in the recovery position just as the paramedics arrived. Stella went to get them as Sheldon began carefully cutting away Madigan's bloodstained shirt.

"Oh jeez-us," Flack swore when he saw the bleeding slashes on Madigan's back.

Mac quickly grabbed the camera from his crime scene gear and snapped a few photographs as evidence, just in case they were needed.

Sheldon nodded at the two paramedics who had arrived, gear in hand, and said, "We've got an unconscious female here. From the looks of her back, I'd say she passed out from pain. Breathing and heart-rate is within acceptable parameters-"

"Donny," Madigan whispered hoarsely, her eyes fluttering as she slowly made her way back to consciousness. Flack had her hand in his in an instant and was crouched down to her level in a flash.

"Hey Maddy. Where you been?" he asked gently.

"Little sister grew up, Donny. Walk-away Joe," she whispered, a tear slowly making her way down her face as she tried to squeeze his hand.

He smiled and said, "Bible and a bus ticket home."

She tried to smile back but she was fading back into unconsciousness quickly. "I'm sorry, so very sorry," she whispered before her eyes rolled back into her head and her lids closed again.

"Sheldon!" Flack barked and the doctor quickly checked Madigan's vitals again.

"She's okay, just out again. We really need to get her to the hospital and get these injuries cleaned up. She's also showing signs of malnutrition, making me wonder when was the last time she ate properly. That isn't going to help her recovery," Sheldon said. "What's her name and age, any one know?"

"Her name is Madigan Sarah Flack, age twenty-four. She's my sister," Flack said, watching as the paramedics carefully loaded Madigan, face down, on to the stretcher and prepared her for transport.

"Then we're going to need her medical history, sir," one paramedic said.

"I can do that, up to about six years ago. After that, I don't know," Flack said, running his hand through his hair in frustration. "I just don't know."