Danny ends up in Gotham while on the run from his family and the GIW. He's on his own. Until a chance encounter where the Joker ends up dead and he ends up with a family.
TLDR: Danny punches the Joker into traffic accidentally killing him and ends up part of the Batfamily as a result
(Will be multiple chapters but ao3 won't let me say 1/? Until chapter 2)
