In the near future time travel is possible. Some believe that small modifications in the past can bring them profit or political gain. They are wrong. Modifications of the past lead to disasters in the present. Mason Edwards and his peers at the National Historical Preservation Institute (NHPI), a military backed, government-funded organization, are dedicated to the ideal of zero tolerance for historical tampering. The way it happened the first time is the way it has to stay. When a modification is detected in the past, Mason, or one of his peers, is sent into the past to make things right. Their mission is to do whatever it takes to insure that the effects of the modification never reach the present. The stress of the mission is severe and sometimes agents crack under the pressure. After a young agent experiences a mission failure and Mason Edwards is sent back to fix it, he becomes quietly obsessed with destroying Mason Edwards and the rest of the NHPI. He joins with Konstantin Gusarov, a Russian dissident with Military connections, and together they plot the destruction of the NHPI. The rogue agent wants to destroy Mason Edwards and the NHPI. Gusarov needs Mason Edwards and the NHPI out of the way so he can make a modification to the past that will allow him to detonate a nuclear device in Washington D.C. Mason and the rest of the NHPI have to act quickly to avoid the nuclear destruction of Washington DC and the murder of millions of people. This is a story of heroism and sacrifice for one purpose, to protect the Historical Precedent and thereby protect us all.