This story is a sequel to She Knows How To Treat A Lady
Ten months after Trixie moving to Ponyville, she starts to disappear from time to tome, witch catches Twilight and Fluttershy's attention and try to figure out what is their friend up to, all while Rarity wonders if Trixie still loves her or not. Rarixie and Twishy!
Cover can be found here!
Her dA page.