Weeks before Poppy is set to migrate to the human colony on Mars, their mother, Arthemise, takes them for one last voyage to visit the floating homestead on the Henderson Swamp where they were raised. On an Earth where to survive in Louisiana in the summer, one must wear a Dune-like body cooling suit, a much-needed family getaway that couldn't possibly last long enough soon becomes an eternity they can't escape when a geomagnetic solar storm powerful enough to produce widespread voltage collapse happens to coincide with a precipitous tropical system of the sort increasingly common not only along the marshy coasts of North America but uniformly and sporadically across the globe.