In Far Rainbow, a calamity is spreading across the planet Rainbow, caused by a science experiment that's gotten out of control. The science doesn't really matter; it's important only insofar as any disruption in human affairs that threatens to destroy lives will be important. What matters to the Strugatskys is how everyone reacts; they've taken their characters to a point of extremity to see what they do, and the results are as recognizable as any real-life disaster story you'll read or see, reported with compassion but with no trace of the excess sentiment, attempt at uplift, or glossing over of selfishness and desperation that often mars such accounts.