Explosive weaves a code-breaking plot around the genuine historical event of the composition by Beethoven of his Eroica symphony, originally dedicated to Napoleon but changed at the last minute when Napoleon declared himself emperor. The author has used the Beethoven's composition to provide a background to her story in which the Duke of Wellington is after the secret formula for a new explosive, dynamite, that he knows is embedded in the score. Only two people have the skills and knowledge to decode it - Devon Caravelle, the daughter of a mathematician, and Gray Dalton, Marquess of Blackburn, an English spy. This is the first problem with the book - the name Devon for a woman is completely wrong for the Regency period, and Gray as a man's first name is also extremely unlikely for this setting; the author really should have done a little more basic research as every time I read the names Devon or Gray I found myself thinking "No, what a terrible mistake!" A French Comte, who is actually in possession of the score but is unable to decode it, also wants to find out the secret of the explosive so that Napoleon, imprisoned following the battle of Waterloo, can be released and can continue his empire-building. The story is an England-versus-France race to find and decode the manuscript in order to head off Napoleon's plans a third time.

Unfortunately, Explosive isn't exciting, despite the potential in the plot. We know that one character has the score at the beginning of the story and that two other characters are needed to decode it; the entire rest of the book seems to be made up of machinations between the three people, with occasional scenes with Wellington, the Marquess of Blackburn's spurned mistress Susannah Treadwell, and a few other people. There's little action, no interesting events, and the dialogue is tedious and unrealistic for the time period. The first half of the book feels rather aimless with the Marquess and Devon meeting, telling each other they need the Eroica score to be extracted from Devon's French lover the Comte, and casting smoldering looks at each other before leaping into bed. The second half is just trying to find the score and avoid the baddies. The situations and dialogue all seem rather unlikely, as do the expectation that Devon, or even the Marquess, would be able to seduce the score from the man who has it - le Comte de Maupassat - and in fact that anyone could bind someone else to them just through sex.

The historical details of Beethoven's composition of the score have been researched, but apart from that most of the book doesn't feel particularly accurate. The characters call each other by their first names very early on in the story, and there seems to be little consideration of the social mores of the time when our characters carry out their actions.

Characterization in this story isn't very convincing, either. Blackburn is a spymaster and does seem suitably divorced from his own feelings and right and wrong, although of course at the end he turns into a wonderful monogamous reformed rake. Devon (that bizarre name rankles every time) just seems weak and irritating and, despite being a famous pianist, barely seems to need to practice. The only really interesting character is the Duke of Wellington, who pops up briefly.

Explosive is a boring and disappointing book which was a real struggle to finish. It's definitely only for fans of Charlotte Mede, and if this is the standard of her writing, I certainly won't become one of those.