"Swear to keep this secret and pledge yourself as my eternal ‘sustenance’ from this day forth—…"

For Ruri, an overworked office worker with a frail constitution, her only solace was Gilbert, her favorite character from the otome game Vampire’s Manor. But one morning, after pushing herself too far, she collapsed… only to wake up in the game’s world, face-to-face with Gilbert himself!

Except, she had reincarnated as Fiona, the doomed fiancée destined to be killed by him!

Now, to avoid her grim fate and stay close to her beloved character, Fiona begins her desperate struggle. But before long, her motivation shifts, from mere survival to a burning desire to save Gilbert, the man who was never truly loved in return…