Thirteenth Sign

what if Sirius wasn't the oldest Black brother? That's it, that's the fic. Read for a story where the Black household on Grimmauld Place isn't quite so overtaken by the trainwreck that is the Walburga-Sirius unchecked clash of titanic personalities as it is in canon. Stay for the adothe adorable Regulus and Sirius Black as eccentric small children