In the future when man has discovered an ability to time travel Charles Hatton (Ben Kingsley) has made a fortune out of a company called Time Safari. Sending people back in to the past to hunt dinosaurs requires the keeping of three conditions: don't change anything in the past, don't bring anything back, and don't leave anything behind. Travis Ryer (Edward Burns) is a geneticist who works for Hatton in the hopes of bringing wild animals back in to existence by studying the living animals in the past. When Sonia Rand (Catherine McCormack) shows up to a post-prehistoric hunting trip party denouncing what they are doing Ryer becomes interested and speaks with her to explain why he is participating in Time Safari's activities. A malfunction in their weaponry on one of their trips causes their carefully planned expedition to go wrong and upon their return things begin to change. When they realize that one of the rules has somehow been broken Ryer seeks Rand's help to get back to the past and fix whatever it is that has happened in the hopes of saving the future.