For eccentric billionaire Howard Christian, a discovery like the mammoth carcass means a chance to add to his toys. So he keeps the find secret while he lines up personnel for his project of cloning a live pet mammoth. Enter Dr. Susan Morgan, elephant expert. It will be her job to make sure a baby mammoth is born some twenty-two months later.
But there's more. Next to the mammoth was found the body of a man, clutching a briefcase-like box which could well be a time machine. The box is dented, no one can figure out how it works, but the Clovis hunters who lived in the mammoths’ era surely did not have the technology to make it. Howard Christian thinks it would be dandy to have a time machine, too. So he hires Matt Wright, math genius, to figure out how it works.
From then on, a dizzying sequence of events occurs, showing that time may not be bendable but it is definitely unpredictable. Matt and Susan become friends, then lovers. Anti-cloning demonstrators trash Christian's lab. Matt has not deciphered the time-travel machine's secrets but the attack apparently activates it. He, Susan, and her elephants are thrown back into the Stone Age. When they return—as unexpectedly as they traveled there—a herd of mammoths, lurking near the La Brea tar pits, is dragged through time with them.
Howard Christian manages to “make lemonade” out of this lemon of a disaster. Matt and the time machine disappear, and only two of the time-traveling mammoths survive. One of them, though, is a baby mammoth, Little Fuzzy, who becomes the feature attraction of a vast new Disneyland- like park. Susan, who saved Fuzzy from the mayhem inflicted on the other mammoths, serves as his trainer and surrogate parent. As time goes on, she concludes that circus performing is no life for the hapless mammoth, and plans a desperate ploy to liberate him.
More than in most novels, everybody ends up where they might not be, except for a last turn of fate of the time machine. To give some idea of the loops this involves, the book starts with chapter five. Chapter one does not happen until the end. Purists may criticize Mammoth—and some have—for not delving deeply enough into the paradoxes of time travel. But there are quite enough paradoxes and puzzles for the typical science fiction reader, amidst a story with a lot of excitement, humor, and human warmth as well.