Chronal Engine

Chronal Engine by Leitich Smith, Greg. paperback edition. ISBN: 9780544022775.

When Max, Kyle, and Emma are sent to live with their grandfather, they think their summer is ruined. But after Emma is kidnapped at the exact time that her grandfather predicted, Max and Kyle are forced to believe his story about the time machine in the basement. To save Emma, Max, Kyle, and their new friend Petra must take the trip of a lifetime — to the Cretaceous period. Soon they find themselves dodging killer insects, velociraptors, and the terrifying T. rex. Can these three contemporary teens hunt down a kidnapper, forage for food, and survive long enough to return home?