Set at the very end of season 2, (so spoilers for that). Lucifer has a long road ahead of him to escape the desert. Revelations and realisations abound, and not just for him. (wanders AU from series 3).

Post Season 2 Finale. Dan goes to confront Lucifer over his disappearing act and lack of answers. What he finds is the last thing he expected. "Let's Wing It!" fic exhange. Lucifer whump. Mentions of self harm. No pairing, just friendship (because I like that Dan just rolls with whatever weirdness he sees around Lucifer now).