This is number three in the Harmony series. Harmony is a earth colony which was cut off from contact with Earth. In the two centuries following, the humans developed psychic powers which were triggered off by the extensive alien ruins which give off psychic energy. In this book, a different viewpoint is taken from the previous two, as we switch to a different couple, although Emmett London and Lydia Smith, since married, do make a cameo appearance.
Unlike Lydia, Elly St. Clair doesn't have a grudge against the ghost hunter Guilds which act like a cross between a milita, the mob and a union for anyone - men mostly - who can resonate with the green energy clouds that manifest around the alien ruins and especially in the extensive catacombs under them. Ghost hunters provide protection for anyone who excavates legally in the ruins, to search for alien relics. The trade in these relics forms a major part of the economy on Harmony. Elly doesn't have ghost hunter powers herself, but instead has a psychic affinity with plants which only her family knows about - mainly because there are only two recognised major psychic talents, ghost hunting and tangling - the ability to resonate with and defuse illusion traps which are also a major hazard of underground exploration - and anyone claiming to have different abilities is viewed as mentally unstable.
In the prologue, Elly calls off her engagement to Cooper Boone, head of her local town Guild, when she discovers he fought a duel over her with another hunter apparently due to Guild politics. Six months later as the story proper begins, she has moved to a city and started a herbal business, utilising her hidden ability to determine psychically which herbs will suit her customers. Then a friend called Bertha, a prospector under the ruins, goes missing, and she calls on Cooper's help, having been told by her mother that he has come to the city. Bertha has been attacked in the catacombs, and it eventually becomes clear that the person responsible is a sociopath who will murder anyone in his way.
As with the other books we have a mystery, a couple who are obviously made for each other but won't admit it or can't communicate - Cooper actually loves Elly, but finds it difficult to show his emotions, and Elly is angry and upset that his dream career from childhood was to be a Guild boss when she wants him to love her as she loves him - and a cute native animal called a dust bunny who is the heroine's companion. This time the dust bunny, Rose, has a penchant for wearing Elly's bracelets.
The author has obviously decided, from this book onwards, where both main characters have powers a bit 'different' from usual - Cooper is a ghost hunter with a difference - that her original set-up was a bit restrictive, so is starting to make this more like her other series set on another colony planet where the humans develop psychic powers (Amaryllis, Zinnia, Orchid). In that series, the psychic abilities were very varied. Having begun to read the book after this one, it's clear that is now the way this series is going to go. Plus a whole new environment has been introduced which I won't explain to avoid spoilers.
A fairly decent read though I actually liked Bertha more than the protagonists who came over as a bit bland, and would have liked to have seen more of her. Again, a 3-star rating.