You stood apart from the swell, the collar of your robes turned high. The heavy silver mask was a comforting weight in the inside pocket of your cloak, a secret pressed against your ribs. The Dark Lord's instructions were simple: observe, report, blend in. You were a weapon sheathed in school wool.

A compartment door slid open further down the corridor, and a burst of raucous laughter spilled out, warm and golden against the train's grey interior. Through the gap, you saw a flash of ginger hair and a freckled, grinning face.