You thrust your wand toward Snape and command him to undo the ritual at once. His face goes rigid with fury, but the curse still grips him, and he turns to the open book with jerking, unwilling movements. The blue flames around the chamber flare as he mutters a countercharm, each word sounding forced through clenched teeth. Beneath the stone, the hidden passage shudders as if something vast and ancient has sensed it is being denied.

The book on the table snaps open wider, pages whipping in a wind that does not touch the candles. Snape’s spell fights the one already laid into the floor, and the chamber fills with the crackle of magic grinding against magic. Quirrell lies still in his bindings, the fallen robed figure too stunned to move, while dust rains from the beams overhead. Your scar burns so fiercely that the room seems to tilt, and you realize the reversal is working, but only barely.