The Doctor returns in this two-parter, following on from last week’s episode we find the Doctor fighting the Sontaren, who have managed to gas the entire planet using their atmos device.

This episode picks up the pace well, not stopping to catch it's breath - which for once is a good thing, no time to pick holes in the plot or try to find some fault with the villains, just pure unadulterated action.

Donna's stand alone infiltration of the Sontaren ship - is the most standout highlight of the episode, with the Doctor guiding Donna through the ship and actually getting her to off a Sontaren guard is wonderfully played - one with the Doctor feeling guilty and Donna's reluctance to do something so dangerous without the Doctor.

Martha has little to do in this episode, her clone not really being much more than a device to stop the nuclear missiles being launched, her evilness just being overshadowed by her 'blandness' - its a disappointment that her reintroduction is so stale and hopefully this will be amended over the next few episodes.

Tennant's Doctor is once again, immensely enjoyable to watch - his interaction with the Sontaren and his selfless act - just to give them a choice before he destroys them - always watch able - in previous episodes he has appeared rather restricted - not here through - his genius and wit used to great effect in this episode.

Unlike previous series' this two-parter is well played out and really enjoyable to watch - and also lots of things to look out for "Are you my mummy" when the Doctor puts on a Mask and Rose momentarily (blink and you miss it moment) appearing on the video screen all add up to the enjoyment.

To be honest the story itself is pretty basic, however the characters are all played well, even Rattigan’s final sacrifice all makes for an enjoyable experience. Lots of complaints have been raised about the foreshadowing on this series, a little more information spread through the series will do it good, rather than just jumping straight into the final two-parter – and I for one welcome more of it, however I agree it would be better served to interwove into the storyline, rather than throwaway lines or image, here or there.

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