This book, like all the other quick reads, is very short, but the shortness adds to the pace the book deserves. It is not only a follow on from the series two episode, School Reunion, but also acts as stand alone story, if you haven't seen the particular episode, it gives a brief look back at the Krillitanes once the Doctor realises who is behind the virus that is threatening the whole internet!
It is also nice to find that the Doctor briefly takes on a male companion for a change. Henry, Brainy Crisps IT head, seems very into his work before we find that he is being used, but then ultimately saves the world from the Krillitanes' plan in the end.
The Doctor also takes on more of a undercover detective in this story, trying to find out what is happening in the Brainy Crisps offices. The story then changes to become more, who is the bad guy? Having a choice out of many people.
Finally, the book is very good, but is not beaten by last years complexity in "Doctor Who": The Sontaran Games ("Dr Who")