Time travel--in a consciously arch (the chapter titles reflect renowned time-travel yarns) and energetically knotty reshuffle. When a mid-air plane crash occurs over Oakland, Bill Smith and his disaster investigation team rush to the scene, only to find oddities: the passengers' watches are all wrong by the same amount (some are even running backward); a pilot reports burned bodies aboard before the collision occurs; and a patently alien device turns up in the wreckage. Meanwhile, in the polluted, war-destroyed far future (a hazy, unconvincing sketch), the human race has degenerated into: disease-ridden, often part-cyborg competents; a hoi polloi of suicidal, idiot ""drones""; lots of utterly brainless ""wimps"" preserved by life-support machines. And operative Louise Baltimore's task is to travel, via temporal Gate, back to the 20th century to save the crash passengers by sending them up to the future--replacing them with suitably tailored wimps to allay suspicion; to prevent a destructive temporal paradox, in fact, Louise (instructed by robot-lover Sherman and the omniscient Big Computer) will have to foray repeatedly into the past, meeting Bill and dealing with the anachronistic evidence. Largely a misfire, then, with humorous, deft beginnings running into inconsistencies and a last-resort explanation--but Titan fans will probably want to investigate.