Odd Girl Out

Frank Compton, an ex-intelligence officer turned reluctant agent for the alien Spiders who run the interstellar Quadrail, is pulled into a new case aboard the trains that link the galaxy's peoples together. With his half-human, half-Chahwyn partner Bayta, he has to untangle the trouble before the parasitic group-mind called the Modhri can use it to tighten its hold on unsuspecting hosts. As always aboard the Quadrail, nothing on the train is quite what it first seems. Third book in Timothy Zahn's Quadrail series, following Night Train to Rigel and The Third Lynx.