Hi, first time poster! Okay, this was a very old fic on fanfiction.net I believe. What I remember was the following:

1: It was before Metatron was introduced to the show, but a version of him was involved.

2: Crowley, Balthazar, Gabriel, and Bobby all were helping fight Lucifer in a second apocalypse

3: Sam was kidnapped partway through and tortured into saying yes to Lucifer

4: Sam ended up dying, and Gabriel went to heaven to retrieve his soul

Thank you so much in advance!