This is a very good 4 part adventure from Jon Pertwee's second season as Doctor Who. In it, a group of seemingly peaceful, gold skinned, and humanlike aliens come with a substance in order to benefit earth. However, beneath the surface lies something much more sinister. Furthermore, at the centre of it all is the Doctor's arch-enemy the Master.
This is another of the adventures set during the third Doctor's exile to earth. It contains all the usual elements of this era - UNIT, Jo Grant, aliens invading, and the Excellent Roger Delgado as the Master.
In addition the DVD contains some interesting extras, including some behind the scenes footage and a look back at the location filming. It may be queried as to why this story was released before others. Personally, I think that Terror of the Autons, the Sea Devils and Frontier in Space are better Master stories. However, there's no denying that if your a fan of the old series of Doctor Who, this is very enjoyable viewing.