Elizabeth Thatcher, a cultured young teacher in 1910, fears leaving her comfortable world in the city. But when she accepts a teaching position in a frontier town, she finds new purpose and love with a handsome Royal Canadian Mountie.
A group of humans arrive on Sirius 6-B to investigate an SOS signal sent out from the planet, which has been supposedly deserted since the destruction of the man-made weapons known as "screamers." Once the squad arrives, they find a group of human survivors eking out an existence in an old military outpost.