Either Side of the Strand — M.C.A. Hogarth

When a routine mapping expedition uncovers what looks like ruins on the planet Theth-129, the crew of the Stardancer is thrilled to have something more exciting to do than catalog worlds only a terraformer could love. Their trip to the world's surface confirms their wildest hopes: their ruins really were made by natives and abandoned long ago, a find of incredible significance. But there's more to this world than an obelisk, a set of painted caves, and a mysterious shoreline. When the sea claims one of the 'Dancer's senior officers, their investigation reveals that the lost civilization might not be quite so lost after all. Alysha Forrest and the crew of the Stardancer have no idea that their way of life is on trial. But before it's over, they'll be asked to prove themselves, and the fate of an entire world is resting on the outcome....