"How or why the rift in time opened up remains a mystery. One moment all was quiet. Next, the skies filled with the raucous "Caw! Caw!" of winged prehistoric reptiles, and then the smooth "Whirr! Whirr!" of gleaming helicopters in hot pursuit . . ." One player controls helicopters and the other pterodactyls; they function the same in game terms. On a turn players moves units (up to three except at the start) up to three spaces in any direction, although damaged units can only move one space. Pieces entering the time warp (the purple ribbon across the middle of the board) must stop. Units on the same space outside the time warp engage in deterministic combat which can destroy and damage units. Each player has bases which can repair their units, but enemy units can destroy the bases. The object is to destroy all the opposing units.