A few weeks later, Harry learns from Hagrid that the dragon egg was given to him by a hooded stranger who had asked him how to get past the three-headed dog, which Hagrid had admitted was easy – music sends it to sleep. Realising that one of the Philosopher's Stone's defences is no longer secure, Harry goes to inform Professor Dumbledore, only to find that the headmaster has just left for a meeting in London. Harry concludes that Snape faked the message that called Dumbledore away and will try to steal the Stone that night.