A/N: I've been thinking about these prompts for a week. I wanted to do something funny. My muse didn't.
"Snape. Severus Snape. Are you home? Please be home. Oh fuck. I really need you to be home," a desperate voice yelled out of the floo in Severus' parents' home. Severus thought it sounded like Regulus, but the pitch seemed higher than usual.
Severus came striding into the parlor; his father forbade him to wear robes at home during breaks from school, but it didn't change the way the lank-haired wizard walked. Severus found Regulus' face amid the flames from where he'd been shouting.
"I need your help, Severus. I need you to promise that you will try to help me. And I need you to promise that you won't tell anyone anything about this, er, situation," Regulus may be clearly distraught, but he was still a Slytherin, choosing his words carefully, getting ready to cover his arse.
"What are you asking me to walk into?" Severus questioned.
"I need you to promise me first."
"What do I get?" Severus wasn't stupid. He also wasn't expecting to hear the answer Regulus chose.
"Anything. I will grant you one open-ended future request."
Severus thought for a moment. What would he find on the other side of that fire, assuming Regulus was at his home? This was Severus' best friend. His brother in all but blood. He suspected Regulus didn't feel quite the same about him. The younger Black still felt some sort of kinship with the other Black, although Regulus would be loath to admit his older brother sill meant something to him. Severus had been looking for a way to cement their brotherhood - a way to finally, fully, supplant Sirius.
Regulus felt whatever Severus maybe walking into to be nearly worth an Unbreakable Vow, a life debt, a magical bond between the two men. It better not involve Lily.
"I, Severus Snape, vow to try my utmost to assist Regulus Black with his current situation, promising to never reveal the circumstances to anyone, in return for a future request."
"So mote it be," Regulus intoned in acceptance.
"Where are you? I'll come through," Severus felt anxious to see exactly what his gamble entailed.
"Grimmauld," the younger boy answered before his head disappeared.
As Severus stepped out of the flames into the parlor, he found a jittery Regulus pacing across the rug. Before Severus could think to say a word, Regulus cast a Muffliato. The green floo flames had covered up the puffy red-rimmed eyes and tear tracks now apparent on Regulus' face. Severus opened his mouth, but the other boy cut him off before he could speak.
"My parents are gone, I don't know for how long, this needs to be fast. I have ordered Kreacher to stay in the basement, but I don't want him to be able to overhear us. I also don't want my brother to be able to recognize your voice," Regulus said as he walked up to Severus and cast a second spell, disillusioning him. "I can't take a chance on him seeing you either."
"Are you going to tell me what the fuck is going on?" Severus hissed.
"Follow me," was all the answer he received.
The two boys proceeded down the hall to the drawing room. The first thing Severus noted upon entering was the smell. The retched smell of sick. Then he saw the body.
Lying on the floor, in a pool of more than one type of bodily fluid, was Sirius Black. Oh hell no. Either Regulus had called him here to dispose of a dead body. Or, the older Black boy wasn't quite dead yet, and Regulus had called him here for something far worse.
Severus stood rooted in the doorway, as Regulus rushed forward, uncaring of the mess as he fell to his knees next to his brother, a fresh sob escaping his lips. He put his face close to Sirius, looking for signs of life. Palpable relief showed on his face as he found something to reassure him.
"You have to help heal him enough to survive a trip through the floo. I'm going to send him to the Potters. I need it to look like he got there on his own – saving him can't be traced back to me," Regulus' voice sounded raw as turned towards the spot where he assumed Severus still remained.
Severus wanted to say no. Sirius Black did not deserve to be saved. As he thought this, he felt the pull of the vow he'd made just minutes prior. Damn it. He walked slowly towards his best friend instead of exiting the room.
He couldn't help the gag as he got a better view of exactly what Sirius laid in. It was difficult to tell if the majority of the fluid around his head was stomach acid or blood, as both were definitely present.
Sirius' head was turned to the side, leaving one cheek lying in the mess below it, with a line of pink tinted foam running down out of his mouth into the liquid soaked into the carpet.
Now that Severus moved closer, he could see the faint rise of Sirius' chest to indicate he still breathed, but he could also hear the rattle that accompanied it. The Gryffindor's lungs were definitely filling with fluid of some sort.
He also noted the way one shoulder and arm were twisted unnaturally as his eyes traveled down the body before him. Sirius' shirt was pulled up, and his stomach already showed signs of bruising; Severus would warrant a guess it resulted from being kicked there repeatedly.
He gagged again, almost being sick himself when his eyes made their way down to the evidence that Sirius had released his bowels at some point during the torture.
Because Severus couldn't deny that this nearly dead boy had been tortured extensively. There was no reason to inquire as to who carried the blame. Regulus managed to keep his inherent soft nature well-hidden, but it still caused Severus to worry during the school term. It was one of the reasons why the older Slytherin knew Regulus needed him.
The body lying there suddenly underwent a series of small twitches, really only notable in the fingers and one ankle. Nerve aftershocks from the Cruciatus. The ankle that remained still was likely shattered too badly to move.
"I don't know what you expect me to do," Severus said angrily, causing the other Slytherin to start. Severus had momentarily forgotten he was invisible.
Regulus turned towards where the voice only he could hear came from and replied, "Any potions you have at home that would help or any healing spells that you know at all. I can't take a chance on using any potions from here in my house or doing any spells myself. My parents will check to see what is missing from the cabinets and cast Priori Incantatem on my wand when they discover him gone."
"Why not use your brother's wand?" Severus asked.
Regulus pointed to the snapped wand lying a little ways away on the floor. The pieces sat below where Sirius' picture used to be on the family tapestry. Severus noted the fresh black burn mark which stood next to Regulus' picture on the wall.
"You do realize my future favor isn't going to be anything small," Severus sighed in resignation as he formulated a plan regarding what he would to need to do.
Prompts used: Regulus Black, a broken wand, a Marauder, Muffliato, Snape