Baldur is killed, everything that remains alive laments, and Byatt's lyrical elegy -- with stalactites dripping, boulders exuding moisture, humid tropical forests steaming, and the lidless eyes of fish brimming to add water to the oceans -- turns the earth into a vale of tears. But the myth, as she says, is "ineluctable", and this mournful outpouring cannot avert the end. Ragnarok follows, taking the form of climate change. Wagner trusted in a cyclical return of life, which is why when Valhalla burns and the Rhine overflows at the end of Gtterdmmerung , the orchestra assures us with one of its recurrent motifs that the world has been cleansed and redeemed by love. Byatt offers no such compensation. Hurricanes -- like the one that flattened southern England in 1987, and supplied her with the climax of her novel Possession -- alternate with droughts. The declining sun emits a light that is "dull red, sullen, like embers". A funeral ship loaded with coagulated rot sets sail: this is Byatt's nightmarish reimagining of the trash vortex, an archipelago of undecaying plastic that swirls in the middle of the Atlantic. In Byatt's view, the saga's villain is Loki, Wagner's Loge, the trickster whom she turns into a connoisseur of chaos, destructive because of his slippery analytical intelligence. Wagner thought that the abdication of the gods would liberate humanity, but Byatt, professing a kind of cosmic Toryism, laments our assault on the divinities who once set limits to our ambitions and held the world