Voldemort attempts to kill Harry Potter after murdering his parents, but the spell rebounds onto Voldemort. Harry is left alive with a scar on his forehead that hides an accidental Horcrux made of Voldemort’s shattered soul.
Voldemort, nearly dead and without physical form, retreats into the forests of Albania where he possess the bodies of various animals to survive for the next decade, waiting. Hagrid, on Dumbledore’s orders, goes to Godric’s Hollow to rescue baby Harry from the ruins of the house (PS1).
According to the story, October 31 is a Monday. In "real life," it was a Saturday.
From the Web
How did Dumbledore, or anyone, know Lily had sacrificed herself for Harry? from scifi.stackexchange
Parental Sacrifice by Rachel
Why Harry and Not the Cat? by Katy