Prologue:

"I do not understand it."

A gnarled finger etched a line into the cold stone wall.

Silence occupied the hollow except for the sound of scratching on the wall and distant wails of the convicts from guilt, regret, and vengeance.

"I do not understand it."

Two occupants were in the room. Neither faced the other, but an unspoken conversation passed the time.

"I do not understand it."

They each faced different corners of the prison cell in Azkaban.

"I do not understand it."

The hag stated to the other occupant in the cell.

"Who killed Cock Robin?"

A twisted smile marred the hideous visage of the old hag. The other did not reply, but the hag didn't care.

She already knew the answer.