Following the trailers, the title and the promotional pictures, it will come as no surprise to anyone that a familiar face returns to Merlin this week.

Following the multi-threaded action adventure that opened the series, this feels like a distinct gear change towards something more intimate. Like Series 4’s ‘A Herald of a New Age’, which also came from the pen of Misfits creator Howard Overman, this is really a tale of personal dilemma.

Coping with a threat that he has brought upon Camelot, Arthur is forced to defend his decisions, as well as the marked differences between his style of kingship and that of his late father.

During the celebrations of his ascension to the throne, Arthur is moody and introspective, confiding in only Merlin. The young King willingly embraces a gift of the Old Religion, yet at the same time clearly still seeks the approval of his father and grieves his loss.

With a preoccupied Arthur, poor Merlin seems to be on the rough end of some exchanges as their relationship slides back towards the fractious. Regardless, he remains supportive and a source of wise counsel, irrepressibly undercutting the tension with humour and some barefaced cheek.

With wider story concerns set aside, there is a strong focus on the core cast and a threat that comes from inside Camelot. Despite the eventful closing moments of ‘Arthur’s Bane’, the round table’s new face is barely seen.

Returning guest star Anthony Head is well served by the story and gives his all, letting Uther Pendragon lose none of his intimidating power. This is not the broken man of early Series 4 by any means! His ghostly pallor is well achieved and director Justin Molotnikov provides excellent poltergeist-style stunts, spills and thrills, employing pretty much every trick in the book as Camelot becomes a highly dangerous place to be.

There are some fantastic moments for both Colin Morgan and Bradley James, as both get to demonstrate their emotional acting chops in a dramatic finale. As much as we enjoy some entertaining moments, with a spooky torch lit chase around the corridors of the darkened castle, this is a story that shines a light on the qualities of loyalty and self-confidence. If perhaps short on Arthurian revelation, it serves as a good opportunity to look at how far both Camelot and Arthur have come with Merlin’s aid.

Airs at 8.25pm on Saturday 20th October 2012 on BBC One.

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