No horcrux AU, PostWar. Harry and Fleur became close friend during his 4th year. Before the end of it he knew that by the time he graduated Fleur would be taken, so he plotted and proposed the idea of going into the protection detail. Fleur wanted something adventurous for a career and the thought of working with Harry made her say yes. (This led her to working the next three years on glamours, defense, etc). Their plan consists of Harry acting as the body guard while Fleur is in change of acting as the body double (with access to polyjuice and glamours it's easily doable).
Skip a few years later and someone is targeting the Malfoy line. Lucius is kill, Draco was injured and is now in a hospital on the continent, and Narcissa has to stay in England until the procedures are completed to move the Malfoy money from Gringotts to the continent.
Cue Harry and Fleur acting as bodyguards for Narcissa. Shenanigans ensue and someone catches feels.