I’m one of this serial’s biggest defenders.  It’s the last gasp of the Season 7 style of storytelling, is the final contribution for both Don Houghton and Timothy Combe, the latter barred from Doctor Who for going over budget, and actually sees UNIT be an international organization.  Despite being set in the UK, this is one of those classic Who serials that feels incredibly global, the parallel plots of Stangmoor Prison, the peace conference, and transporting the missile really creating that.  It’s also fascinating for how it engages with the international community, care is taken with the script to not paint the Chinese characters as exotic caricatures and keeps the language as close to correct as possible.  Chin Lee as a character is genuinely compelling despite being a victim of the Master.

Roger Delgado as the Master gets to really make this fascinating second impression, while it has similar setup to Terror of the Autons with the character making an alliance, as the serial goes on Delgado relishes the chance to seeing what the Master deeply fears.  The same can be said with Jon Pertwee as the Doctor, his fears reflecting his experiences in Inferno and the evils he has fought and can no longer face due to his exile.  Katy Manning is always a delight with Jo getting to be in the middle of the prison plot while Nicholas Courtney once again excels in the action sequence near the end of the serial.  Dudley Simpson being promoted to essentially the main composer also adds leitmotif.  Truly an underrated gem.