This late novel by Tiptree, better known for her short stories and short novels, has not been popular with either reviewers or readers. It has a number of flaws, but it held my attention throughout.
There are a large number of characters, but they are all so nicely delineated that I had no trouble remembering who was who. The plot involves a small terrestrial caretaker base on an alien planet whose inhabitants had earlier been horrifically physically exploited by earthmen, a base which receives an unusual number of visitors who have supposedly come to see the spectacular final passage of a supernova shock wave through the system... a supernova triggered by one of the novel's main characters, and a supernova which apparently destroyed an entire race of intelligent, artistic creatures and their ultimate artistic creation. Naturally the last surviving alien, in disguise, has come to seek revenge, while three criminals in not very believable or effective disguise have come to torture the natives a bit more to extract some (as usual in sf) impossibly rare and valuable secretion that only pain and torture bring forth, kill everybody at the base in a staged accident, and then depart.
The plot works only because the three main characters are incredibly stupid, lazy, easily distracted and passive in reacting to the very obviously looming "situation". And a preposterous fantasy element (the fact that time can run backward in fits and starts during the passage of the supernova shock wave) allows several sympathetic characters who have been killed off or mutilated beyond recognition to be restored to life (with mixed results, I might add).
Given the glaring flaws, however, the novel ultimately succeeds (at least for me). There are many likable characters, many suspenseful situations, an action-filled climax, and some plausible yet unexpected plot twists.
This is far from Tiptree's best work, but she was clearly getting some ideas important to her off her chest and into print, and the discerning reader is the ultimate beneficiary.