It was nice to read a Target novelisation by someone other than Terrance Dicks. Especially that this one was by the actor who played Harry Sullivan. It was fun when I started reading as I was like, WOW adjectives! How different for a Who novel. The writing was definitely better. The description of the alien taking over was much more impressive than the green bubble wrap used on the show! The description of Sarah crawling through the tunnels was also much scarier. It was also funny to see that Harry might have had feelings towards Sarah! Or rather towards the "old girl".
This is one of my favourite Sarah and Harry episodes. It was good to read the novelisation.