Even those who previously were alien to the charms of Torchwood, the ‘adult’ Doctor Who spin off, were left applauding by the end of 2009’s five-episode serial, Torchwood: Children Of Earth. For this was ‘adult’ in a good sense: no cheap swearing, no sex and violence for the sake of it. Rather, a challenging, thumping good tale for grown-ups, superbly told.

Its story, as so many Torchwood stories do, has alien intruders at its heart. Far more creepily, though, there’s the small matter of all the children on the planet being controlled at once. It’s thrillingly realised, and genuinely gets under your skin. The drama is further complicated by the dishevelled state that Torchwood itself is in when we find it, as it’s once more tasked with saving the world from disaster. Rarely has it been so ill-prepared for such a major threat.

To tell you more about the plot of Torchwood: Children Of Earth would be to spoil it. It’s a dish very much best served cold, and an outstanding piece of science fiction television. It also looks its best in high definition, courtesy of a quality Blu-ray release. We’re not talking Hollywood blockbuster feature film standards, but it’s not too far behind. And it’s as good a looking a piece of British sci-fi as you can find on Blu-ray to date. Simply: an outstanding serial, and a very good disc.

Torchwood’s third series takes a bold and ambitious step, as it moves away from its usual 13-episode formula, replacing it with a five-episode season, based around one core story. Broadcast over five consecutive nights on its original transmission to keep the momentum going, DVD arguably ups the ante still further, offering an opportunity to devour it all in one sitting.

And it’s an opportunity well worth taking up. Following the dark denouement to its last season, Torchwood: Children Of Earth sees Captain Jack Harkness and his team facing a massive threat to the planet. Put simply, every single child on the Planet Earth has suddenly stopped. Aided by Gwen and Ianto, the onus is firmly on Captain Jack to save the day.

But the threat is arguably as big as anything Torchwood has previously faced. When a warning that something is coming follows the sudden stopping of the children, the mystery deepens further, and further events soon make the Torchwood team the hunted. The end of the world could well be coming…

Torchwood: Children Of Earth is frantic, exciting science fiction television, that benefits enormously from its new format. The leads are on their usual good form, led by John Barrowman, and there’s also strong support from The Thick Of It’s Peter Capaldi and Charles Abomeli. And with the assured direction of Doctor Who regular Euros Lyn behind the camera, it’s a classy all-round production.

It also leaves some interesting questions about where Torchwood goes next exactly. But while you’re waiting for those to be answered, then Children Of Earth is an excellent way to pass the time.