This was a really good time travel Sirimione (Sirius Black & Hermione Granger) fanfiction and I really liked Regulus in this story. All the Marauders were fun to get to know in this story and the epilogue was cute. 

Archive of Our Own: https://archiveofourown.org/works/10911969

Fanfiction.net: https://www.fanfiction.net/s/12489418/1/Hourglass