The second of the three two-part tales that make up the final series of The Sarah Jane Adventures opens with a jinxed Native American totem pole and an unusual rainstorm over London: a downpour of trout. Yet despite these suitably bizarre and potentially extraterrestrial trappings, this is a story more concerned with alienation than aliens.

‘This looks dead fishy,’ Clyde remarks at the beginning, opening a barrage of puns and ‘It was this big!’ size gags which, allied with the introduction of Sky – a much younger character than Sarah Jane’s other assistants – indicate an intention to bring the show back into line with CBBC’s youthful audience demographic.

But although spooky totem poles and ancient curses are very much the staples of adventure stories for all ages, the mature underlying themes of Series 5 which began in last week’s ‘Sky’ – loneliness and abandonment – remain very much to the fore, and it’s these concepts which dominate as Clyde finds his friends mysteriously turning against him.

Daniel Anthony’s performance is excellent. Clyde’s miserable bafflement at the sudden, inexplicable antipathy towards him is the highlight of the episode; and when even the ATMs and the weather turn against him, leaving him tearful and desolate, it’s one of the strongest scenes yet in The Sarah Jane Adventures. Unfortunately, there isn’t a great deal else of substance to bolster it.

The sequence where some of Clyde’s old footballing friends turn on him is terribly weak (they fall into the tired old trap of talking about beating him up rather than actually doing it, giving him a chance to escape) while the three surly security staff at the exhibition of totem poles, despite being light years from Dick Van Dyke and the other geriatric guards in Night At The Museum, are no less convincing.

Most distressingly of all, the other regulars are demonstrably below par. Anjli Mohindra fails to carry off the hysterical hostility that the script demands of her and Ace Bhatti goes way over the top, almost hissing with unrealistic anger at one point, while Jocelyn Jee Esien struggles to evoke estrangement as Clyde’s mother (although given she has to try and put something realistic into the dismal line, ‘I feel like I’ve had my soul sucked out of me’, who can blame her?) and young Sinead Michael is only slightly less wooden than the totem poles. Only former Skins star Lily Loveless, playing a vastly more sympathetic character than her current role in BBC Three’s The Fades, brings very much to the supporting cast and even she only appears twice.

Fortunately, the overall story is sound and – based on the evidence of the teaser, at least – the second half is brighter, livelier and more exciting than the first, with everyone resolutely back on the money and even Sky appearing more animated than she has done previously. It’s a relief after an opening instalment which has much to recommend it but ultimately – fish pun klaxon – flounders.

Airs at 5.15pm on Monday 10th October 2011 on CBBC.

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