The Bonds of Blood and Magic

During Harry's first visit to Diagon Alley, he discovers that he has a twin sister that was hidden away from him. Using the power of a blood spell at Gringotts, he summons his sister so he can meet her. Soon after meeting her, the last Potters discover some terrible secrets that Dumbledore attempted to keep from them. The two decide to forge their own path…(Harry/OFC. TWINCEST.)