Thank you again for all the reviews! Also, you might want to go back and read the first part of Chapter 2; I accidentally left out the scene where Regulus learns that Harry is the Master of Death, but I added it back where it belonged.

Part Three

"I want to start this now." Lily Potter's voice is quiet but forceful.

"We cannot rush it, my dear," Dumbledore says, peering at her with a faint frown. They're in the Potters' drawing room, standing around a conjured platform that Regulus suspects is made of pure glass. On it sits a silver bowl swirling with bright blood mixed with a Pensieve memory. Regulus has to keep his eyes away from it, as the swirls seem hypnotic. "It is imperative that we get it right the first time, or the blood magic might consume us."

Regulus snorts. Dumbledore peers at him over his spectacles in turn. Regulus averts his eyes only enough to make sure that he won't be taken advantage of by Legilimency, and shakes his head. "It isn't nearly as evil as you make it out to be."

"We will do it my way or not at all."

Dumbledore speaks pleasantly, but the wrinkles tighten at the corners of his eyes. Regulus inclines his head. "Of course, Headmaster."

He manages to make it sound gracious and like he's conceding. From the way that Dumbledore eyes him, he suspects Regulus is making fun of him, but doesn't know how. After a moment, he shakes his head and turns back to the bowl. He lifts his wand, and the swirls of dancing blood and memory orient towards him and spin slowly around.

"Do you think this will work?"

Regulus glances over his shoulder before realizing that Lily is speaking to him. He nods. "If he has a blood connection to you," he adds, after a moment. "Your theory sounds plausible to me, but it might not be true."

"That he comes from another dimension?" Lily smiles with only her lips, keeping her eyes locked on the bowl. The swirls of blood in it are definitely dancing faster now, following the Headmaster's wand. "I don't know if I should hope for that or not."

"Why not?" Regulus asks curiously. "From what I know, he may be your only chance to have a child."

"He may indeed," Lily says, not taking offense, although James is glancing towards them with a frown. Regulus holds back what he wants to say, which is that Lily is the most interesting out of the Potters and Sirius, but still not nearly interesting enough to hold Regulus's attention permanently. "But if he come from another dimension, presumably he has parents there and is working to return to them."

"And?"

"And I feel as if I would do everything in my power to prevent him from going back," Lily whispers.

Regulus considers her some more, then turns sharply back to the bowl at an exclamation from Dumbledore.

There's a dark mass forming above the bowl, squiggles of black and red light tracing their way through the air. Regulus can see that they're spelling out letters, as well as forming a face. He leans forwards eagerly, only a little resentful that he couldn't perform this divination himself first and see the face of his mystery in private.

The red and black light claps together and forms the face that Regulus remembers from Diagon Alley two days ago. Wide green eyes, tumbling black hair, and pale skin. He didn't notice before, however, the scar that sticks like a lightning bolt out from underneath the boy's fringe, or the glasses that perch on his nose.

Words have formed beneath the face, scribbled in dark red calligraphy. Harry James Potter. Master of Death.

Regulus stifles his annoyance at the gasps and screams. He did hope that he would be the only one to know that.

But at least he might have more help to find him now. His mystery.

Harry. It's the sort of plebian name that Regulus might have known the Potters would name their son—his identity seems established beyond a doubt by the first and last names—but oddly enough, it suits him. The name seems to settle into Regulus's bones and stretch like a cat making itself comfortable.

He wants to get to know Harry. He wants to know him in depth.

Lily is making small, fierce noises. Sirius and James are still exclaiming, probably surprised that the blood tracking worked, or that it didn't cause them all to fall down with bad cases of evil or something. In the commotion, it's not easy to notice Dumbledore's silence, but Regulus's eyes are drawn to him.

Dumbledore seems shaken. He's staring at Harry's face with more concentration than it deserves, and clutching his wand. Regulus tilts his head. Does Dumbledore see Harry as a rival because he's powerful? Because he's the Master of Death?

He certainly seems to have seen Regulus that way at some points in the past, after Regulus defeated Voldemort. On the other hand, sometimes he tried to make nice with Regulus and present himself as the only one who would truly understand him, because of being the only other British wizard in recent memory to defeat a Dark Lord.

Now here is someone else, someone powerful that Dumbledore can't control and hasn't planned for. Regulus ducks his head to hide his delighted smile.

"Look at the image!"

Dumbledore's voice is sharp. Regulus snaps his gaze up again. He has no objection to looking at Harry as long as the picture of his face lingers, but he doesn't think that's what Dumbledore means.

And it isn't. There's a swarm of grey motes rising from the bowl of blood and memories, dancing around the image of Harry's face. Regulus stares. He's never heard of anything like this with blood magic, but he ignores the way that James and Sirius are falling back, brandishing their wands and shouting. He doesn't think that the magic itself will harm them.

He's right. The grey motes settle, hovering, around Harry's face and shoulders, and the image stirs enough to show Harry ducking his head and closing his eyes. Regulus leans close.

The motes are tiny Dementors, reaching out scaly hands as if to grab hold of Harry's ears and hair.

The image dissolves.

Dumbledore catches his breath and staggers back from the bowl as if a tether has snapped. Perhaps it has, although Regulus has never had such a violent reaction when he performed blood magic in the past. Dumbledore is unused to it, of course.

"What does that mean?" Lily whispers. She has taken a stride towards the bowl and has her hand lifted as if to trace the features of the face that is no longer there. "Does it mean our son is a victim of the Dementors?"

Regulus shifts in place, the memory of Aunt Cassiopeia's words returning to him. The Master of Death is not native to these shores. He draws the intruders with him.

That does sound as if Harry comes from another dimension. But Regulus wonders how the Dementors became intruders. After all, they've guarded Azkaban for centuries. Perhaps it just means that they're intruders into the domains of wizards and witches that were supposed to be safe from them.

"Do you know something, Master Black?"

Dumbledore is peering at him again. Regulus shrugs. "Mrs. Potter said the other day that she thinks perhaps this young man has come from a different dimension," he says. "And I don't think it's a coincidence that he appeared right when the binding for the Dementors fell. Do you think that perhaps his stepping from one dimension to another made the binding break?"

Lily whirls to face him. "My son did not do that!"

"I'm not saying that he did it on purpose," Regulus says. Indeed, given the books Harry stole from Grimmauld Place, he doubts it. But that will remain his secret for now. "Only that such a powerful wave of magic flooding into our dimension could have weakened the binding without his intending to do so."

Lily's lips grow bloodless. She turns back to Dumbledore. "The magic should have allowed us to track him, shouldn't it? We need to reach him as soon as possible and get him out of danger."

"It should have allowed that," Dumbledore murmurs, staring at the bowl. "The image of his face should have lingered until we established a connection with him, and then changed into a map. But the Dementors appeared and disrupted the connection."

He turns to stare at Regulus.

So do James and Sirius. Sirius is sneering, lightly tapping his fingers on his elbow. "Something you want to tell us about blood magic, Reggie?"

"Maybe it doesn't work as it should on dimension travelers," Regulus says blandly. He thinks Harry's connection to the Dementors probably interfered, but he doesn't intend to say that. He has his own thoughts to think, his own secrets to keep. "I know that I've never seen a result like this before."

Sirius's eyes narrow, but James speaks up before he can. "We have to find Harry and bring him home, obviously. What's the soonest we can try that magic again?"

"Why should we think it would work any better than it did the first time?" Lily demands, her hair trembling like fire around her shoulders. She spins to face Regulus. "Do you think it is because he's a dimension traveler?"

"I think it's at least a possibility," Regulus says, and spreads his hands when she glares at him. "I don't know. As far as I remember, my parents never used it to track anyone who wasn't born in this world."

"Then we need another way." Dumbledore strokes his beard. "We will not rely on the vagaries of blood magic."

"We never should have in the first place," Sirius mutters.

This time, it's Lily and Sirius who descend into bickering, soon hot enough that it might go into full-fledged shouting. Regulus leans back against the wall, ignored, and lets his mind roam slowly around old memories.

Yes. He doesn't know if the Dementors get in the way of ordinary blood magic, or Harry's status as a dimension traveler did, but he does know a way that ought to work, which relies on knowing someone's full name.

And Dark Arts, of course.

Regulus lets his lips quirk, but only on the inside, since Dumbledore is watching him. Outwardly, he maintains a bored face as he watches his brother squabble with his best friend's wife.

Regulus will do this right. And while he does think that he will probably introduce Harry to the Potters—eventually—he wants the privilege of meeting the Master of Death and speaking with him for the first time by himself.


"I'll need you to leave the room and not disturb me, Kreacher."

Kreacher is lingering by the door of the library. Regulus glances over his shoulder, a little impatient. He's cleared the rugs from the floor to reveal the ritual circle traced in silver salt and sand, a permanent one that never changes no matter how many times someone might try to brush it away (like Sirius did as a child). The light of the waxing moon will shine through the windows soon. Regulus needs to be ready.

"Master Regulus," Kreacher whispers. "What if this be like the locket?"

Regulus relaxes a little. He can see why Kreacher is nervous. The last time Regulus told him to leave and let Regulus do what needed to be done, Regulus nearly died in a lake full of Inferi. He would have if Kreacher hadn't disobeyed.

Regulus puts out his hand. Kreacher comes forwards to clasp it, staring intently into his face.

"I promise that I will be safe," Regulus murmurs. "The particular kind of magic I am going to do is entirely under my control. I know my name, and I know the name of the target. I'll seek him, and bring him to me if all goes well, but I promise that I'll let the thread go if it seems like it might be endangering me."

Regulus can't conceive how that will happen, but then, the blood tracking magic wasn't supposed to go wrong, either. And it costs him little to make the promise to Kreacher, who is already standing taller.

"Kreacher be right outside the door, Master Regulus." Krecher raises his hand and points towards the door without taking his eyes from Regulus's face. "Kreacher be waiting."

Regulus nods, and waits until Kreacher closes the door. Then he turns and faces the window again, lifting his face. He sits cross-legged inside the circle of salt and sand, and he can already feel the magic that Blacks have practiced here for generations rising around him.

It strikes him, suddenly and like a blow, that Kreacher is his only friend. Perhaps that is one reason he is so interested in Harry Potter, because it would be someone interesting who doesn't know his history, someone Regulus could talk to.

Regulus shakes away the distracting thoughts without moving. The light of the waxing moon is shining through the window now. Regulus extends his hands in front of him, palm up, elbows resting on his knees, and closes his eyes as his mind ranges out in front of him.

Harry James Potter, Regulus Arcturus Black calls you.

Distantly, Regulus feels the first pull of the tether, the kind that would have tied Dumbledore to the blood magic. He is momentarily grateful that Lily and James never had children. Then there might have been two people of that name and with that face in this world, and Regulus might have called the wrong one.

Of course, if Harry wasn't a Potter, then Regulus wouldn't have to share him with the Potters, either.

But he lets that thought pass away like a sigh, like nothing more than a ripple of wind on lake water. He breathes in, the air rushing through his lungs, and breathes out, the exhale stirring up a glimmer of frost in the air.

Harry James Potter, Regulus Arcturus Black calls you.

This time, there's definitely the feeling that he's caught someone. Regulus can feel a hook under his navel like the world's slowest-acting Portkey. He firms his muscles with as little motion as he can manage. It's possible the ritual will pull him to Harry, but he would prefer that not happen.

He will stay here, and Harry will come to him.

Harry James Potter…

The chant of Harry's name and his own, entwined, burns through Regulus's head and heart and body and soul. He loses track of how many times he's said it, loses everything except the tightening feeling under his navel and the way the moonlight moves across his skin.

He has until the moon departs to complete the ritual. If Harry isn't here by then, Regulus will know it didn't work, and he'll have to collaborate with the Potters on the alternative to blood magic that Sirius has already proposed.

Abruptly, the wards shift around him. Regulus starts, but doesn't allow himself to be distracted, still drifting along in the self-immolation of the chant.

Harry James Potter, Regulus Arcturus Black calls you!

The chant surges up through Regulus's heart and head harder than he meant it to, and he finds himself on his feet, in absolute blackness except for the slight glimmer of a wand's light. The moon has passed from the windows, and crouching on the floor in front of Regulus is Harry James Potter.

Regulus gazes at him, heart as full with wonder as Lily Potter's eyes of tears. Harry stares back at him, mouth open. He has crooked white teeth, and his hand clutches a wand that makes Regulus tilt his head.

He's almost certain that he saw that wand earlier today, in Dumbledore's hand.

"What have you done?" Harry whispers, the first words that he's spoken to Regulus directly. The incantation to summon the Patronus doesn't count. He straightens up and stares at Regulus, gathering himself as if for battle. Regulus has never seen a more enchanting sight. "Do you know what's going to happen now?"

"I introduce you to your family in this dimension?" Regulus offers. His voice is croaky, and he staggers a little, worn out by the effort of the name summoning. He steps out of the ritual circle and reaches for Harry's arm.

Harry starts to shake his head, and then his face falls. A second later, a flat expression replaces every sign of emotion. "They're here," he breathes.

The room fills with cold.

Regulus turns around in what feels like slow motion to face the Dementors clustered against the wall. Once again, the wards did nothing to keep them out. It feels like there are more than in Diagon Alley, although Regulus has no idea, because he can't see. He gropes for his wand, hating the slow numbness that invades his limbs.

He doesn't hear Harry speak the incantation this time. He only knows that the room suddenly fills with light and glimmering warmth, and the stag canters back and forth in front of them, tossing his antlers and stamping a hoof warningly.

The stag is only normal size this time, not the house-large beast he was in Diagon Alley, but it doesn't matter. Regulus reaches out a hand, and discovers that shining hide, for all that it looks metallic, hides bunching and quivering warm muscle.

"You know, I'm getting really tired of doing this," Harry snaps, glaring at Regulus as if the Dementors are all his fault. Regulus only stares back, enthralled, and Harry makes an impatient noise. "When I come near wizards and witches, I draw Dementors with me. I tried to make a short shopping trip to Diagon Alley, and it happened. So I was in the Muggle world, and they weren't bothering anyone. Let me go back there."

Regulus takes a moment to find his voice. It's a wealth of information where he didn't really think to get any, but it's also so unexpected that he doesn't know how to deal with it. "Dementors aren't frightened away by Muggle buildings or technology," he says at last.

"Did I say they were?" Harry is spitting the words like a wand spitting sparks. It's beyond impressive than he can hold such a conversation with Regulus, glaring at him all the while, and hold his Patronus without effort to corral what feels like fifty Dementors. "I only said that witches and wizards weren't there. Let me go back."

"I want to know you," Regulus whispers. "I want to know who you are."

"Too bad."

Regulus half-smiles. Yes, that sounds like James Potter's son, or maybe Sirius Black's godson. "Too late," he says, and gestures at the Dementors. "Can your stag destroy them? Do you think more will come before the morning? I can at least raise the sort of wards that ought to keep them out, the way I did in Diagon the other day."

Harry scowls. "Yes and no."

"Well, then."

Harry scowls harder, but turns to his stag and lays his hand on the beast's neck, whispering words too soft to hear. Regulus is certain he hears "Prongs," which would make sense as a nickname.

The stag rears and charges forwards. For a moment, the light he casts flashes off the walls like a thunderbolt, and Regulus shudders at the sight of how many Dementors are huddled there. But the light tears into them, and they scream and puff into dust and ash.

The stag turns back towards Harry, who dismisses him with a weary wave of his wand. In the darkness and silence that are left, Regulus becomes aware of how cold he is. He holds out a hand to Harry, who sighs and accepts it.

"We should get you to bed," Regulus whispers, in part because he needs to go there himself.

"Raise the wards that you said you could do first."

In the end, Regulus has to call Kreacher back into the room and draw on the elf's power to raise the wards that spread around the house in whirling spiderwebs of magic, different from the Black family wards that have proven useless against the Dementors several times now. Harry stands by with his arms folded and watches, frowning, but shakes his head when Kreacher says something about getting him something to eat.

"I ate," he says.

Regulus eyes his scrawny frame and opens his mouth to comment, but Harry adds, "I could sleep, though," and slumps to the floor without a pause or a word further, out cold.

Kreacher scoops Harry up quickly enough to prevent him from hitting his head, muttering something that sounds like "stubborn" and "Master Regulus." He glances sidelong at Regulus, who nods.

"Put him in Sirius's old room," he says. "And ward the front door."

After all the effort he went to to capture the Master of Death, he's not escaping because Regulus made a careless mistake.

Regulus follows Kreacher up the stairs to Sirius's room and lingers to watch Harry tucked into bed. He rolls on his side when Kreacher draws the blanket over him and sighs deeply.

Regulus half-smiles, lingers a moment more to watch Harry's steady breathing, and then gives in to Kreacher's prodding to eat something before he goes to bed.

He looks forward to the morning with a passion that he hasn't felt in years.