Quicksilver begins with the Doctor returning Constance home to 1944. After some awkward goodbyes, the Doctor suddenly finds himself in the midst of the capture of a fugitive and Constance discovers she is a little later home than the Doctor lead her to believe and that her husband, Henry Clarke, has been lost in action.

By the end of the first episode, the Doctor and Constance are helping the fugitive, Kinvar, escape his pursuers, the Vilal, and end up in 1948. Unknown to them, the Vilal have discovered a discarded wedding invitation of the Doctor’s, outside the TARDIS, which leads them to kidnapping Flip Jackson from her wedding reception and transporting her to 1948 as well.

This is a hugely fun adventure with some good emotional beats. When Constance discovers her husband is alive and well and trading with aliens in Vienna in 1948, her anger is palpable. With Flip thrown into the mix, having coincidentally met with Henry after arriving, disorientated, in Vienna, Constance assumes he is having an affair with her. When Ana, Henry’s actual new partner, arrives – all bets are off as far as Constance is concerned.

The growth of her friendship with Flip when they realise they share a relationship with the Doctor is one of the highlights of the story. Putting the restrained, mannered Constance with the carefree, ever-so-slightly vulgar Flip, is a stroke of genius and one which definitely pays off in Scorched Earth. It has echoes of when Rose met Sarah Jane or Donna met Martha but manages to go a bit deeper and, because they are so different, makes for a really interesting dynamic.

The secret behind Kinvar and the Vilal is also an interesting idea – Kinvar is basically their battle computer, bred specifically to make the decision for their forces of armoured, troll-like creatures. Having developed a conscience, he wants to run away from the battle they are embroiled in – against glass-like praying mantises, the Zerith – but the Doctor manages to convince him that he can use his abilities to end the conflict rather than perpetuate it.

All of this plays out on the background of 1948 Vienna where an uneasy alliance between the allies in the aftermath of the war shows how the seeds of the Cold War begin to be sown with the various factions still searching out technology which will give their country the edge – in this case alien technology provided, foolishly, by Kinvar to Henry Clarke, back in 1943.

The climax of the story goes ever so slightly silly with a giant 6th Doctor booming out across Vienna but the image of Constance clambering on the outside of a Ferris Wheel and firing potshots at the enemy is huge fun – as is the reaction of the male officers from various countries observing it.

If anything, Colin Baker is slightly overshadowed by everything else in this story but the combination of Connie and Phillipa is what makes the story. The conclusion of the minor Mr Clarke subplot first introduced in Criss-Cross is satisfying and the alien plot has enough original elements to keep in interesting throughout.

Historically, this story reminded me of how the shadow of WW1 was cast across a number of stories set after 1918. World War Two may have finished by the time most of the events in this story happen, but it’s shadow and the uneasy alliances created in its wake are sure to influence any stories set in this time period.