A chap wakes up with amnesia after an accident and discovers he's developed magical powers! If anyone comes within fifteen or so feet of him, they instantly die.
He meets a woman, turns out she was a passenger in his car during the accident, who is the only person immune to his radius of death. When she's within the radius, she negates its effect. They then decide to try and find out who they are and what the bloody flip is going on.