> 'Merlin': Is it the right time for the BBC fantasy drama to end?
One of those lingering Merlin plot threads is the 'dark Gwen' arc, and this week's episode certainly does take a surprising turn a mere two minutes in when it's revealed that Gwen and Morgana's latest scheming session is being spied on by Arthur (Bradley James) and Merlin (Colin Morgan).
It always makes for a refreshing change when the frequently clueless Arthur is seen to be in the know and he quickly takes steps to thwart Morgana, but has he made a mistake in taking on Mordred (Alexander Vlahos) as one of his trusted few?
Gwen's new-found villainy is quickly revealed to be the result of powerful dark magic - let's face it, she was never *really* going to turn out to be a proper baddie - which sends Merlin on a quest to uncover the secret of her salvation. Rather than simply lingering on the sidelines, looking concerned, as he is often wont to do, Colin Morgan's lead is again pleasingly proactive here.
But our hero's spurned by the hideous Dochraid - one of this show's most memorably gruesome creations, last glimpsed in series four's 'Lancelot du Lac' - forcing him to lash out at the creature with his enchanted blade. It's the most ruthless Merlin's been since he killed Agravaine... and we're loving it.
To save his Queen, Merlin must summon the White Goddess and convince Gwen to willingly enter an enchanted lake, but he knows that only Arthur can reach his wife. The King is once again forced to embrace magic here and the relative ease with which he again accepts sorcery is telling - a hint at developments yet to come, perhaps?
Of course, Arthur would never trust Dragoon again - given the role Merlin's older self apparently played in Uther's demise - but the moment when Gaius (Richard Wilson) drops Merlin in it, forcing the warlock to disguise himself as a woman, is a genuine laugh-out-loud moment. Colin Morgan clearly has a ball in the scenes that follow too, outrageously camping it up as the old crone.
In fact, despite its dark themes, 'With All My Heart' does make plenty of room for humour - witness Merlin, Gaius and Arthur larking about as they attempt to secretly transport a drugged and unconscious Gwen outside of the castle grounds...
But the levity doesn't last for long: a rockfall traps Arthur - 127 Hours style - and though Mordred arrives in the nick of time to save his King, does his arrival portend an even worse fate? Another moment we've been waiting on for weeks finally surfaces here, with Morded confronting Merlin about their ambivalent relationship, which remains one of the show's most interesting dynamics.
As the episode reaches its climax, Morgana (Katie McGrath) unleashes the fiery power of Aithusa upon our heroes and Merlin willingly leaves Mordred to her mercy - but it transpires that the knight is more than capable of defending himself from her onslaught...
The capacity of Mordred's power has never truly been explored. Is he more powerful than Morgana? More powerful than Merlin? Should we expect a three-way battle in the series finale to decide who's the mightiest magician of them all?
Ultimately of course Gwen is won back over to the side of good. The sequence in which Arthur implores her to return to him is powerfully played by on-screen lovers Bradley James and Angel Coulby - there's shades of the Buffy season six finale, in which Xander (Nicholas Brendon) begged a corrupted Willow (Alyson Hannigan) to let go of her rage.
Whether intentionally or not, the news of Merlin's demise has come at the perfect time, with series five having gained a new impetus. Following a brief lull, the show is back on track with this week's instalment - if the show's final four episodes can match 'With All My Heart' for quality and pace, then we're in for a treat.