Magic mishaps (Merthur AU)

Summary: 15 years later Camelot is prospering, Lancelot Pendragon is becoming a great Prince, but one day he found an old spell in a book in Gaius' Chambers he chants the spell and ends up 11 years into the past when his parents were 19 and 23 also Uther is still alive. how will the young warlock survive until he can go back home... set in season 3 episode 4