Mercy Shall Follow Me (Lord Peter Wimsey), by Raven
I almost never read (or want to read) fanfic for books, and Dorothy Sayers' Lord Peter novels are no exception. This, though, written for Yuletide, is a subdued and excellently written epilogue to Busman's Honeymoon, which means it's a followup to one of my favorite scenes in the novels. (If you've read it, you know what I'm referring to; if you haven't, you can't read this fic.)
Made me smile and feel appropriately moved.