This novel, IMO, signals another step in the return to good story-telling by Susan Johnson. To some extent, it is in the style of Blaze and Taboo; however, it is not quite up to the level of either. The promise of the opening is not quite fulfilled as Lucy Attenborough is the threat that never really materializes, and the Empire turns out to be a caricature of itself.
The Flynn-Jo story is a good one, and the reader can sense the temptation to reduce this romance to the common denominator that many of Susan Johnson's last few stories, bar the previous, have been. Temptation, notwithstanding, Johnson doesn't succumb, so there is actually a plot and a weaving in of this story with Blaze, Silver Flame, and the others of that set.
Force of Nature is a pleasant surprise and a good reminder that Susan Johnson still has what it takes to write a story with a plot and interesting characters that one can care about. Flynn Ito is a wonderfully reluctant and weary warrior, and that helps Force of Nature to fit into the the Braddock-Black storyline and even answers questions the reader might have about why do Flynn and Jo never appear in any of the other stories. Jo's character is consistent with that of the other women in the Braddock-Black series. She's a strong-minded career woman who is not shy about going after what she wants. Are they likeable characters? Yes, they are. Are they as memorable as previous Braddock-Black series characters? Not quite. Even though Jo and Flynn have a crisis towards the end of the novel, the distress they face as a result of the contributing circumstance could easily have been avoided. In that respect, it seems artificial.
The novel is a good one for those who like Susan Johnson, and I do. Worth the price? As proof that Susan Johnson is on the way back, it most definitely is. Buy it, read it, enjoy it.