There's something about Atlantis that makes 5 million people tune in each week, so if you haven't had a gawk at BBC's Merlin replacement yet then we suggest you get on that bandwagon quick sharp. Tonight Hercules visits a witch in an attempt to win Medusa's heart, but events take a dangerous turn when he releases a potent but toxic enchantment that threatens to turn his burgeoning hope into unbearable grief... Can Jason save the day?