Connie Willis, All Clear
For more than 1,100 pages total, these young historians (Polly, Eileen and Mike) struggle to either find a working drop that will transport them back to their own time or to be found by those they feel certain will be coming to rescue them. Yet "the entire space-time continuum" seems to be working against them. Things keep happening to block them, divide them, distract them and thwart them in every way imaginable. They fear that they, sent only to observe history, will not just alter it but cause Hitler to win the war. Further, they fear they and many of the people they have come into contact with will have to die as time struggles to correct itself.
Time itself becomes a character in the novel as the story becomes increasingly metaphysical. Is time God or is God time? The Christian symbolism at the climax of the novel, set in St. Paul's Cathedral, makes it clear, if it's not already, that Willis gives her tale religious implications.
This second novel, even more than Blackout, can be tough going, and some readers will wonder if it is worth the effort, but the last 50 to 100 pages, when Willis untangles all the many plot threads and finally makes it "all clear," reward us magnificently for sticking with it.