So the Doctor(Tom Baker) and Romana (Mary Tamm) have found two of the segments of the Key to Time. Now onto the third segment: the segment found in The Stones of Blood. The Stones of Blood is the one hundredth Doctor Who story but unlike 2009's Planet of the Dead it is never acknowledged in the story. It is weird to think there had been one hundred Doctor Who stories by this point and it is a credit to the classic series that they hadn't run out of ideas by this point.

Sadly, for the one hundredth story The Stones of Blood isn't one of the better serials. It is very imaginative but does at the same time it feels a little run of the mill. The serial sees the Doctor and Romana arrive on Earth during the then-present day, near a group of standing stones called The Nine Travellers. They find old archaeologist Professor Amelia Rumford (Beatrix Lehmann) and her partner Vivien Fay (Susan Engel) who are studying the stones and find dried blood on the ground. The stones are revealed as being a species from the planet Ogros called Ogri; they need blood in order to survive. Meanwhile, the Doctor is put on trial by the Megara - justice machines searching for a wanted criminal known as the Cessair of Diplos - for breaking the seals on locked doors aboard a prison vessel in hyperspace. The Doctor and Romana must stop the Ogros from absorbing blood from innocent people and help the Megara bring the Cessair of Diplos to justice.

The idea of vampire stones is a nicely eccentric one and a concept that wouldn't work on any other show but the serial doesn't explore the eccentricity behind the idea enough. I can't help but think Douglas Adams would have been a better fit for this serial; the Ogri would no doubt have been better executed and the Megara could have been a neat if madcap satire for strict law systems. These ideas whilst very inventive ones by writer David Fisher don't feel as though they are given justice by him and could have been better handled in a more capable writer's hands.

I couldn't really care for 'Vivien Fay' (or her true identity) either. She's a bit bland and her real identity seems to be a revelation that comes out of nowhere. When it's revealed who the Cessair of Diplos is, I'm not really given enough reason to believe she is accountable for the murder crimes she has been accused of. She's certainly not one of the show's best-written characters and neither is Professor Amelia Rumford, who whilst the characterisation isn't bad doesn't really stand out. David Fisher seems to be a writer who is better at big conceptsand ideas than he is at characterisation and narrative. He would have probably made a better storyliner for a soap than a writer for a sci-fi drama.

This is the serial where Mary Tamm's Romana shines though. I feel like she comes into her own as the first Romana in this story and feels like a much more engaging companion to the Doctor. In the previous stories she feels a bit too stiff but here it's like Mary Tamm's worked out the right balance between Romana's authoritative way of speaking and showing a bit of her personality underneath. Whilst The Pirate Planet showcased Tom Baker at his best, this is a good showcase for Mary Tamm.

K9 also gets more to do in this serial than in the previous two; he feels like more a part of the TARDIS crew than he did in The Ribos Operation for example and he does generally seem to move the narrative forward, especially when he helps the Doctor fight the Ogri or stays behind whilst the Doctor and repairs the projector that allows the Doctor and Romana to visit hyperspace with Amelia. I wish K9 would return in the new series as I think he would be a perfect match for Peter Capaldi's Twelfth Doctor (NB: He nearly returned in Last Christmas).

Whilst The Stones of Blood may not be the best Doctor Who story, it has been of some inspiration to future Doctor Who stories. The idea of standing stones hiding a secret (such as how they are the Ogros in this serial) has been used in The Pandorica Opens/The Big Bang with Stonehenge's Underhenge. And then there's the idea of a justice system hunting an alien criminal that has been used in 2007's Smith And Jones and 2010's The Eleventh Hour. It has clearly been an inspiration for some new series writers and that's something that should quite rightly be applauded.

Overall, The Stones of Blood is not the greatest Doctor Who serial and certainly not one worthy of being the one hundredth story. It suffers from bad characterisation with its supporting characters and feels a bit run of the mill. The Stones of Blood does contain some nice ideas however - such as the vampire-like 'stones' and the Megara - that have been influential in the stories of the new series. It's also a good showcase for Mary Tamm's incarnation of Romana, whilst K9 feels more like a part of the TARDIS crew than he did in the earlier Key to Time stories.