Theo knew arctic research was dangerous. He didn't know those dangers involved getting sucked into other worlds, changing into a bird, and having to somehow find a way home. Turns out it was more dangerous than he thought.
There wasn't a better private investigator in Chicago, not before Dakota's near-fatal car accident. But thanks to a new class of medical implant she's been brought back, to investigate one of the oldest mysteries of earth and Equestria alike.
Humanity's space exploration ultimately took the form of billions of identical probes, capable of building anything (including astronauts themselves) upon arrival at their destinations. One lands in Equestria. Things go downhill from there.