It's a big gamble for an author to end his first book about a Cavalry regiment with the Battle of Waterloo: where can we go from here? Well, since our hero is British, the answer is India, obviously. Hervey is sent to India - and thereby unable to marry his fiance as planned - to undertake a special mission for the Duke of Wellington.
Of course, things don't go to plan: Hervey ends up mixed in local politics and incipient warfare between the princely states. There is a beautiful Rajah's daughter who is causing Hervey no little consternation; nearly as much as "the Nizam's daughters" - a number of long cannon, the best artillery in India.
We get a good look at regency India here, with a number of characters providing surprises of one sort or another. Hervey is still very proper: he is definitely a man you would trust with your wife or sister (like Hornblower, and unlike Jack Aubrey, or especially James Bond!). This does not make him less interesting though, and certainly not boring. He is also not free of pride - when appointed to command the Rajah's armies, he demurs on pragmatic grounds, rather than doubting his abilities to do so (a point then deftly made by the Rajah).
The story is probably a little bit better than the telling, but its more than enough to hold your interest, and keep you reading the series.