Star Trek: Balance of Nature (Star Trek: Starfleet Corps of Engineers Book 27)

In the wake of the catastrophic events of Wildfire, P8 Blue returns to her homeworld, only to find herself caught up in a web of intrigue. Strange disappearances among her fellow Nasats and odd happenings throughout her homeland have stymied local authorities. Due to her experiences with Starfleet in general and the S.C.E. in particular, Blue is asked to aid in the investigation.
What they turn up will lead to a terrible secret from the Nasat's past, and it will take all of Blue's ingenuity to save her people -- and an entire world....