You have descended forty-seven levels below Diagon Alley in pursuit of a vault that our records — etched in goblin-forged iron since 1474 — have never contained.
Vault 404 was never assigned. It sits between the dragon enclosure and
a regrettable incident we do not discuss. The cart has returned empty.
The torches have gone out. Whatever you were seeking
was not here, is not here, and — in all likelihood —
never shall be.
We suggest you retrace your steps. The goblin behind you suggests the same,
rather more urgently.