"Merlin's"magic trick: Getting darker, staying light Colin Morgan, left, as Merlin and Katie McGrath as Morgana in a scene from "Merlin." Shine Ltd./FremantleMedia Enterprises Here's a wizard's trick: Can "Merlin" get darker and stay light at the same time? It's a question of tone and the obvious challenge for the SyFy series as its plots push into more sinister territory but the creative team tries to hold on to the humor that widens the show's audience to an all-ages group. Here's a look at an exclusive clip from the Feb. 13 episode, "A Servant of Two Masters," which finds a bewitched Merlin acting as a reluctant assassin. I've written before that "Merlin" is a favorite in my house - it really is geared for family viewing - and apparently we're not alone. The U.K. import is a hit at home (the finale of the fourth season aired on Christmas Eve to a record audience of 8.1 million) and it now has a foothold here with its biggest U.S. audience with a 20% increase over last season's numbers. Consider the numbers for Jan. 27 episode: That one pulled in 2 million viewers, which beat the most recent SyFy episodes of the far-more-promoted "Being Human" (1.4 million) and "Spartacus: Vengeance" (1.3 million). Big kiss! It's our Valentine's Gift Guide Year of the dragon: Firebreathers reign "Game of Thrones": Martin's season 2 worries "Alacatraz": Unlocking secrets "Hobbit": Serkis says Gollum in his DNA Supernatural'finds future in the past