Last week saw Team SJ running on the spot somewhat in ‘The Empty Planet’, as the story (about an empty planet on which youngsters Rani and Clyde were the only inhabitants) felt just a bit like filler. This week, the storyline feels very much like the kind of filler that Doctor Who itself used to do – and quite often, quite clumsily – but here is done with verve, and not a small degree of wit.

The vague starting point for the adventure is Sarah Jane and the team investigating the possible sighting of an alien at a rather large junk shop. Before anyone has a chance to even whisper ‘contrivance’, the gang are split up into different time zones to hunt for some mystical metal that can change the course of history. Here, it really kicks into old-style Who, since the finding of the artefacts is really the subplot.

First, the team have to battle against some seemingly unconnected problem, and that’s even before dealing with the challenge that each artefact has been disguised to blend in with the local time and place. So far, so ‘Key To Time’ – and in fact, there’s nothing here to suggest that this isn’t the Key To Time from that Tom Baker adventure (and indeed, there’s a fair amount to suggest that it might be), but this manages to fit the demands of The Sarah Jane Adventures very well.

Clyde is given a Boy’s Own style adventure (lots of running, jumping, guns, and basically winning the war), Rani, currently bereft of female friends of her own age, gets to have a bonding session with a very special girl her own age, but with a lot more responsibility, while Sarah Jane herself gets the ‘grown-up’ story in a haunted house tale that shamelessly steals from one of the cleverest ideas from Quatermass creator Nigel Kneale – which is perhaps fair enough, since The Sarah Jane Adventures long ago based its science of ghosts on another Kneale story (The Stone Tape).

Triple viewpoint storylines are always a very tricky affair (as we’ve indicated, Doctor Who itself, which used to this sort of thing pretty much every week, didn’t always do it well – there would often be at least one companion that would get left behind, sometimes literally), but in this two-parter, it feels like the story couldn’t have been told in any other way. Instead of a storyline strand feeling surplus to requirements, it feels like the characters are growing and developing further (we’ve mentioned before that Rani is already proving herself to be a suitable candidate for TARDIS travel, and here is enough evidence for us to say it again, if for no other reason than when she obliquely references Martin Luther King’s speech about the quality of someone’s character as opposed to the colour of their skin).

In short, this is fun, witty, and occasionally scary, and not likely to be an embarrassment to any of the aging Who fans who make up the show’s core audience.

Airs at 5.15pm on Monday 8th November 2010 and Tuesday 9th November 2010 on CBBC.