A happy appointment, but now with a little added poignancy...

I sometimes have this recurring nightmare that I'm back at school. The horror. A horrifying prospect of 11 years of homework, detentions, rotten kids and equally rancid school dinners (the sort that would leave Jamie Oliver telling the chefs responsible to Pukka Off). If you'd offered me a million pounds to relive all 11 years of school, you'd luckily get to keep the money – which would at least pay to repair a John-shaped hole in the wall.

So the evil that is school is like gold dust when planning settings for a wacky new episode of Doctor Who. The somewhat overdue setting came to fruition in 2006 with School Reunion, a story that also marks the return of Sarah Jane Smith and K9.

For the old-school fans, this is a treat and a half. There's always that fan excitement when it's announced that a face from the past returns to the fold, whether it's the comeback of past monsters in Doctor Who, or The Brig and Jo turning up to swap notes with Miss Smith in The Sarah Jane Adventures.

In essence, School Reunion is a kind of loose pilot for the hugely successful spin-off show. It's the sort of adventure that could fit snugly into the CBBC schedules, combining elements of Buffy The Vampire Slayer and The Demon Headmaster to great effect. Just as importantly, School Reunion is the story that cements the fact that NuWho is still the same show that TV audiences fell in love with back in the 1960s. In Eccleston's season, we'd had Daleks, a Cyberman head and a blink 'n' miss it glimpse of UNIT, but now we have the return of two of the most popular companions to have travelled with The Doctor – not to mention a quick trip down memory lane as Sarah Jane Smith rattles off past adventures and adversaries to an arguing Rose.

"School Reunion proves that you can bring an old companion back to rapturous applause when you do it right"

It's quite a brave move bringing back Sarah Jane, both for new converts and dedicated fans alike. There's the risk that younger audiences may not have known who Sarah Jane was, or why The Doctor was making such a big deal over her. A bigger risk was alienating the fans of the show with a Sarah Jane who may not have tallied with the plucky journalist who had endeared herself to millions in the 1970s. About the only criticism you could make is the rather odd implication that she's been carrying a torch for the Time Lord – I never really got the impression that she was making big, mooning cow eyes at the curly headed one. To my tiny mind, their relationship was one of two best friends, one which combined childlike wonder with grown-up realism (They had their fair share of arguments, you know). But somehow, lurve never really entered the equation. So to suddenly imply that Sarah's been pining for the age-old Gallifreyan (“There was this one guy – I travelled with him for a while. But he was a tough act to follow”) seems a bit weird.

But otherwise I've no complaints at all. School Reunion proves that you can bring an old companion back to rapturous applause when you do it right. The return of Sarah is largely handled in a mature, intelligent and at times, poignant fashion, thanks to a superlative script from Toby Whithouse, and of course, from a scene-stealing turn from the late Elisabeth Sladen (and given the recent terrible news of her passing, the story's ending is even more of a tear-jerker). It's a smart move to look at a companion who's had to adapt to life without The Doctor, and more to the point, The Doctor is forced to provide somewhat awkward answers as to why he suddenly left her in the lurch – in Aberdeen, of all places.

And evidently, The Doctor's initially none too forthcoming when providing answers – especially in the café scene, when the two have a heart-to-heart over old times. “Did I do something wrong?” asks Sarah, re-opening those old wounds. Poor old Sarah has spent all those years wondering what she did to make The Doctor take off like that, adding that all the sights and wonders of the universe made a return to Earth seem like a poor reward. The Doctor tries to insist that she put her experience in the TARDIS to good use by investigating, but fails to come up with a good reason as to why he never come back. And not only that, he's had several new models in tow, following Sarah's departure. “Ho ho! Mate! The missus and the ex!” chortles Mickey at a slightly flustered Doctor. “Welcome to every man's worst nightmare!”

"David Tennant knocks this one out of the park in one of his best first season performances"

Tellingly, The Doctor can never properly give Sarah a straight answer – but when Rose presses him on the subject, he reveals that his long life is the key to all this. “You can spend the rest of your life with me,” he explains. “But I can't spend the rest of mine with you. I have to live on. Alone. That's the curse of the Time Lords.” It's that age old dilemma of whether you would want to live forever – a tempting prospect at first, but one that becomes a poisoned chalice if you take on board the fact that your loved ones grow old and die before your eyes. The Doctor's lonely life is emphasised – not for the first time during the Tenth Doctor's run – it's probably the most effective study of this facet of The Doctor, and a smart counterpoint to this incarnation's manic zest for life. For the first time, we get to see the older, wiser side of this Doctor (also seen in the intense poolside confrontation with Finch), and David Tennant knocks this one out of the park in one of his best first season performances – he's still engaging without being too annoying in his chirpy enthusiasm (his delight at seeing Sarah for the first time), but adding that necessary gravitas when required in the more serious scenes.

And Elisabeth Sladen perfectly plays Sarah as that older, slightly saddened version of everybody's favourite Metropolitan journalist. Take that scene when she first realises that she's met The Doctor, who comes strolling out of the shadows, Dirty Den style. Going from incredulous to delight through to edgy bitterness through to teary anger through to the thrill of adventure in just a couple of minutes. Not easy to do, yet Sladen does it as easily as putting on a jacket.

It's also great to have K9 back, and John Leeson is as brilliant as ever as the tin dog. Listen to some of the DVD commentaries when Leeson slips into his K9 voice, and you realise that his clipped robot tones are untreated, which is some accomplishment. When you think about it, getting sad over the destruction of a silly robot dog sounds like a pretty dumb thing to do, but yet thanks to Leeson's endearingly warm portrayal, K9's self-sacrifice is rather touching.

The themes of loss and death form a suitable backdrop to the main plot of the story. This time around, The Doctor's pitted against a hungry bunch of bat-like things called Krillitanes, who scavenge and steal elements of the races they have conquered throughout history. They've recently decided to up their game by attempting to crack what's called the Skasis Paradigm, an apparently impenetrable equation that lets you have control of the building blocks of the universe when decoded. So what better way to attempt to crack the code with an army of unassuming kids, whose souls and imaginations are perfect keys to unlocking the code?

The Krillitane Leader, Finch, a man who's oilier than the school chips, even attempts to woo The Doctor over to the dark side with the prospect of using that power to help save planets and keep races living forever. “I could stop the war...” murmurs The Doctor, as he ponders over such a tantalising opportunity. It's only Sarah who brings him back to Earth with the harsh reality that everything has its time and that everything dies – a point proven when The Doctor decides to throw a chair at a screen containing the code. Hey, those TV screens have feelings too, you know.

"The message is admittedly none too subtle in School Reunion, but it ties in nicely with the themes of loss and death that run through the Davies era"

But it all sums up a common thread of Davies-era stories, in that death is the only reality. Some characters like Cassandra, Lumic or a resurrected Pete try and cheat death. Captain Jack, at times, feels like a freak for being the man that can't be killed. And even The Doctor is woken up by this harsh reality – for example when he mourns Madame Du Pompadour, or when he faces his own mortality in The End Of Time. The message is admittedly none too subtle in School Reunion, but it ties in nicely with the themes of loss and death that run through the Davies era.

The downside of this is that somehow the Krillitane plot is too incidental. It's practically shoved into the janitor's broom cupboard, while The Doctor, Sarah and Rose sort out their differences. School Reunion could and should have been a perfect candidate for a two-parter, since the 45-minute format just doesn't fit the combined might of dewy-eyed nostalgia and a good, well-told adventure. The Krillitanes are quite an interesting race, but not enough is made of them. Same goes for Anthony Head's superb performance as Finch – he's not given enough screen time, and could have been put to better use in a two-part story. When he is on screen, he makes for a memorably smarmy baddie with a repertoire of cool one liners (“You poor... thin... child” or “Forget the shooty dog thing”). Not only that but his freakishly wide-eyed screeching is enough to send the kids diving behind the sofa. I don't know – maybe he found a way to teleport out of the end inferno and live to fight another day. If there's a guest actor crying out to be brought back for Round Two, then it's Anthony Head as Finch.

"The production team are wasting Billie Piper's acting talents on a character that's losing her appeal more and more by the day"

Another iffy element of School Reunion is Rose. Inexplicably, Rose's usual cheery, feisty persona has been dematerialised and replaced by Alexandra Forrest from Fatal Attraction. Sadly, School Reunion marks the point when Rose's petals have fallen off to be replaced by a paranoid, possessive grump. No sooner does Sarah Jane enter the equation, she's leafing through the Old Granny Putdown Thesaurus like a woman possessed. “Where are you from, the Dark Ages?” she sneers at poor old Sarah, before stomping around with the expression of a sulky Big Brother contestant who didn't get her weekly shopping allowance.

This all reaches a head in that bizarre sequence when she tries to outdo Sarah Jane with her experiences in the TARDIS. At least she realises her folly, but up to that point – boy, this is hard to tolerate. Especially when you consider how well crafted her character was in the last season. Now, Rose is either being too smug and too big for her designer boots, or she's carrying on like a one-woman Jeremy Kyle audience. Which is a shame, when you consider how the production team are wasting Billie Piper's acting talents on a character that's losing her appeal more and more by the day.

Mind you, at least Mickey's coming into his own – in fact, it's a blessed relief when he decides to hop along for the ride at the end (Rose tuts and rolls her eyes, of course). Noel Clarke's also come on leaps and bounds, and he provides a likeable, comedic turn that has luckily toned down the excesses of some of his early performances. Mickey also gets a good portion of the great lines, whether he's lamenting his status as the tin dog, or whether he's spluttering about how he doesn't scream like a girl. Incidentally, in The Doctor's case, this is a case of the pot calling the kettle black if ever there was one, giving his propensity for screaming like a woman on a seemingly non-stop basis in his next season.

This is another well made show, and also the last to be directed by the talented James Hawes (although New Earth was to be the last one completed in a pressured set of recording sessions). There's a lot to admire here, from the excellent location filming at the school, well-designed monsters and subjective POV shots from the Krillitane point of view. Anthony Head aside, the guest cast don't really have a lot to work with, although Eugene Washington is very good as the under-used Mr Wagner. Even the kid actors aren't too bad, which is something of a minor miracle.

And so to that last scene in which The Doctor finally says “Goodbye, my Sarah Jane!”, a scene that still threatens to make me bawl like a baby. It's a poignant ending because there's all that history between the two characters, so their final goodbye (well, at the time – they'd go on to meet again, of course) feels like the closing of the last chapter. And of course, the tear-jerking factor – in hindsight – has also been heightened because of Elisabeth's tragic death.

It caps off what's one of the most touching stories in the rebooted Doctor Who. I'm normally a bit wary of the over-emotional stuff, but when it's written and acted with such heart and class, as it is in School Reunion, then it's hard to resist. School Reunion is not only a triumphant comeback for two popular companions, a delightful bit of nostalgia for the faithful, but a clever, well-judged look at the core themes of Doctor Who which never gets too schmaltzy or cloying. A big highlight of the season – and more to the point, a big tribute to the considerable acting talents of Elisabeth Sladen.

John Bensalhia limbered up for this mammoth task with a full four-series review of Blake's 7, and writes professionally and recreationally all over the web. Check out his portfolio of work here.

Check out John's previous Doctor Who review, Tooth And Claw

See also:

Liz Sladen: "Don't forget me"

Elisabeth Sladen: 1948-2011

Exclusive: Anthony Head talks Merlin, Sold and his £2000 phone call

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