An average but intense story for the Sontarans, as we move further into the Williams Era.

The Doctor has developed a lot, becoming sillier and more light-hearted when around the Sontarans. His interactions are always fun, and he has some great moments which show off why he is clearly the most popular Doctor. There's some decent continuity in his reaction to the Time Lords interfering once again, such as when they show up in Colony in Space, the Mutants and Genesis of the Daleks. Leela has an extremely thrilling storyline, teaming up with Vilhol and then having to go to such extremes - this leads to a strained relationship between the two travellers, and I can't wait for them to expand this in the future.

Strang is a really intimidating foe, and is pretty ruthless for a Sontaran (none of that funny Strax nonsense), even killing an entire squadron of Sontarans in his first scene. The idea that accompanied this was a very fascinating concept, and I'm surprised it hasn't been done before. The Doctor's reaction to not be able to knock him out was a O_O moment. Strang's clones ramped up the threat, being practically invulnerable and I had no idea how they would be defeated.

There aren't many side characters, since practically everyone in the story wants to kill the Doctor, so I'm just going to talk about the Sontarans in general. They are pretty decent, but aside from Vilhol, who bonds with Leela far too well, and Strang, they have nothing that special about them.

Overall, quite a good story in terms of characterisation for one Sontaran and developing Leela and the Doctor's relationship, but aside from that, quite generic.