This is a stand alone novel from David Drake set in contemporary America.

The engineering professor and his students had been told that the device they were helping build was a time travel device that would allow the to travel back to the Mezoic but as problems callibrating the device multiply the group and their friends and colleagues on the university staff learn that the travellers aren't from Earth at all but are a group of aliens intent on using Earth as a staging post in an attack on their even more alien enemies.

Almost thirty years on from its copyright date it's strange how dated the contemporary actions feel - not just the technology but some of the social interactions between the sexes (rather interestngly reversed in the humanoid aliens). What action there is is as intense, violent and almost random as you would expect from David Drake the Vietnam veteran. ( )

ZB7