A truly exceptional read that serves to capture everything great about the TV series while including an all-new plot. The Fifth Doctor and Turlough are perfectly presented as an uncertain but well-fuctioning team, Turlough's essential selfishness being counterbalanced by the Doctor's inspiration to do the right thing while the Doctor's wide range of knowledge allows the Fifth to help the expedition even without leading them like his other selves might have done.
Even the use of the rarely-seen Kamelion works well, the android getting some effective characterisation as he provides vital aid in the resolution of the crisis (AND in a manner that accounts for Queen Victoria's actions in "Tooth & Claw" into the bargain; talk about precognitive!), while the supporting cast are well-presented and provide truly engaging personalities for the readers to enjoy.
And as for the setting...
Exceptional location, intriguing villains, and an engaging mystery that culminates in a highly satisfactory manner that ties up all loose ends while making it clear that all concerned have been affected by their time with the Doctor; EXACTLY as it should be.