So, series two is starting to take form, with the second episode just as good as the first. I needn't bore you with the trivial talk of how much the series has improved, or how much was riding on this episode being as good as the last, because you all know that as well. Needless to say, you can all take comfort in the fact that you won't be disappointed with this episode.
I remember sitting in maths lessons and thinking that Pythagoras was the trickiest equation I would ever have to see, until I saw this episode, where the problem is whole lot deadlier. Sherlock and Watson are on the case to solve the mystery of two dead mathematicians on the brink of solving one of the greatest math's problems: P vs. NP. Sounds very straightforward, but this episode is far from straightforward.