The Philadelphia National Archive uses the machine to fish people from the past for the sole purpose of studying humanity. Trouble is, the Archive crew doesn't know how the time machine works. Luckily for them, they happen to fish only geniuses and top warriors out of the past. These geniuses from ancient times are capable of figuring out how the time machine works. But given that the geniuses are also warriors, there is little that the people of 2308 can do to stop them from reverse-engineering what turns out to be a "discontinuity black hole" time machine.

There's Benedetta, the brilliant warrior peasant born in 1473 who happened to be Leonardo da Vinci's friend and protégé. Benedetta worked with da Vinci on a flying machine (not quite a time machine, but close enough). There's Ivar, the Viking from 1,300 years ago who throws away his ax to hack machine language and networking protocols. And there's computer cracker Fluffy, aka Jonah Kirkpatrick, who's convinced that all of the transported ancient people are really subroutines in a virtual-reality game. Jonah comes from the year 2008.

These geniuses want out of their Archive prison, and they begin looking into the laws of 2308. Are they full citizens of Philadelphia, with the right to live freely? Will they be able to leave the Archive prison without falling prey to lethal modern diseases? But the one real question of this book is: Can a peasant, a Viking and a computer nerd reverse-engineer a "discontinuity black hole" time machine in an outlaw lab equipped with three atomic force microscopes?

Too much fun to be taken seriously

Time's Child is fun, quirky and creative. Readers cannot help but love Ivar the Viking, a womanizer with huge muscles who quickly learns English and Latin as well as how to thread round magnets for use as spacetime discontinuity containers. Benedetta is irresistible as Leonardo da Vinci's protégé, who finds lathing spacetime discontinuity containers as relaxing and easy as spinning wool. And as the two ancient geniuses work to take the time machine apart molecule by molecule, the reader even smiles, albeit slightly, at the arrogance of the stereotypical computer nerd of 2008, who smugly asks, "Can't they script it?"

The book is lively and full of surprises, as long as the reader doesn't take the science or the plot too seriously. After all, it's a stretch to think of Ivar as an overnight computer hacker extraordinaire who also happens to conquer electrical engineering, the physics of black holes used as power sources and reverse engineering with atomic force microscopes. It's another stretch to think that Benedetta's experiences with Leonardo's flying machine suffice to give her the knowledge to start conquering the science of a far-future time machine. It's inconceivable how she becomes an expert at strong encryption.

Don't these people, smart as they are, need to know a little bit about calculus, physics and engineering before they get started disassembling and building time machines? And questions do arise about how these ancients all learn modern English fast enough to converse and read smoothly in the language from the moment they pop into 2308.

A very pleasant romp, Time's Child sets up hopes for these characters: Where they will go and what they will do. But at the end, the brilliance of the creative ride just flickers off, leaving the reader in the dark.