Y/N and Theodore Nott have been inseparable for years, the kind of friends who drift in and out of each other’s homes and lives with an ease that only comes from long‑standing trust. Theo has a reputation for being charming and flirtatious, the sort of person who never seems to take romance seriously, and Y/N has always accepted that as part of who he is. What she doesn’t know is that behind his casual exterior, Theo keeps a private side of himself carefully hidden — a side shaped by his interest in structured, consensual power dynamics and the world of BDSM. He has never shared this with anyone in their circle, least of all Y/N. When Y/N figures out his little secret, instead of being unsettled, she finds herself intrigued by the structure, communication, and trust involved. When she eventually tells Theo she wants to try it, he reluctantly agrees to guide her himself. What begins as an experiment for Y/N and a protective compromise for Theo slowly becomes a shared secret that reshapes the foundation of their relationship.