The Beginning

When 14 year old Amen walked into a quaint little bookshop in Soho London before work they did not expect what was about to happen. In the next few hours they would become a mix of an angel and a demon and become immortal. Aziraphale and Crowley didn't know they would become so attached to this random kid but when they realized it they knew they were in for a wild adventure.
Ineffable husbands later in the story.