It is late when Kreacher finds you, his large eyes shining in the dark doorway of your room at Grimmauld Place.

“Mistress,” he croaks, voice rough, trembling. His gnarled hand extends toward you, clutching a small, neatly folded letter. The parchment is familiar, the edges precise, the handwriting on the front unmistakable.

Regulus.

Your stomach drops as you take it with shaking fingers, unfolding it slowly as if it might vanish if you move too quickly.

I’m sorry I could not be stronger. I hope you find the freedom I could not. Do not follow me. R.A.B.

Your breath hitches, eyes burning as you read it again and again, the words blurring until you can barely see them. Your brother’s name feels like a brand on your skin, a promise breaking inside your chest.

“No,” you whisper, clutching the letter so tightly the parchment crumples. “No, we promised. He promised.”

You stand abruptly, anger cutting through the fear. “Kreacher, where is he? Where did he go?”

Kreacher’s eyes widen, head shaking as he wrings his hands. “Master Regulus told Kreacher not to say, Mistress. Master Regulus said not to follow.”

You grab the elf’s shoulders, your tears hot on your cheeks. “Kreacher, please. We promised each other. We were going to live for each other. I’m not letting him die alone.”

Kreacher looks at you, and for a moment, something soft flickers across his ancient features. You are his master too, the last of the Black children who ever treated him with kindness.

“Take me to him,” you beg.

There is a crack, and you are gone.

The cave is cold, the air sharp with the smell of salt and stone. The black water laps at your boots as you step forward, your wand casting a pale glow across the cavern.

Regulus is there, standing before the basin that holds the emerald liquid, the locket glinting under the light as he holds it tightly in one hand. His wand is raised in the other, his jaw set, eyes cold with the determination that has always terrified you.

He does not hear you at first, whispering something under his breath as he stares at the potion.

“Don’t.”

Your voice echoes across the water, small but sharp.

Regulus freezes.

Slowly, he turns, and for a moment, you see your brother again—not the Black heir, not the Death Eater, but the boy who once swore to protect you, who once held your hand under the dinner table when your parents shouted.

His eyes widen, horror flashing across his face. “No,” he breathes, shaking his head. “No, you shouldn’t be here.”