The Helping Hand

What if Merlin, who had been living for 1,300 years, was pulled back into action when, after the deaths of Harry Potter's parents & Voldemort's fall, Morgana manages to open the gates of Avalon enough to send a message, instructions for freeing her, across. Voldemort, because he isn't quite human at the time, receives the instructions and decides to resurrect her. (pairing ideas?)