This is a really strong story, especially to listen to now in the context of things like Black Lives Matter. It's an adventure that sees Susan's friends at Coal Hill School mind controlled by a mysterious piece of alien technology, and subject her and her grandfather to abuse because they are aliens and 'don't belong here'.

It's a unique take on immigration with a Doctor Who twist, the Doctor and Susan obviously being from Gallifrey and not Earth, so residing on the planet away from where they really come from. The way that Susan's friends and the gang of youths turn on the Doctor and Susan is nasty and abhorrent, and you really find yourself feeling for them.

I loved the stuff with the sinister teacher at Susan's school too, Mr Rook, who at one point I actually suspected to be the Master because of the mention of him carrying a fob watch and was surprised when he just turned out to be a human being who previously served as a colonel in World War 2.

Overall, a very strong start to this collection of special fiftieth anniversary stories.