Star Trek: Ring Around the Sky (Star Trek: Starfleet Corps of Engineers Book 37)

STARFLEET CORPS OF ENGINEERS The Tellarite colony world of Kharzh'ulla is a planet of many wonders, but its greatest feature is the Ring, a massive orbital construction, serviced by a series of "space elevators." During the Dominion War, the elevators were damaged by a Jem'Hadar attack. Now, a year and a half later, the elevators have weakened to the point that the entire Ring may collapse, endangering the planet's population -- unless the crew of the U.S.S. da Vinci can save them. But Kharzh'ulla also contains several deadly secrets from Lieutenant Commander Tev's youth. In order for the S.C.E. to save the planet, Tev must face more than one demon from his past...