The novel comprises:
a two-page Prologue;
twenty six numbered but untitled chapters;
a five page Epilogue.
The type is small and there is very little blank space between the chapters. Nantucket is still in the prehistoric past. The Prologue is dated 2 After the Event and the Epilogue is 10 A.E. Chapter One begins with a date of 8 A.E., followed by 2 A.E. in brackets, but presumably this will be explained.
The Prologue begins by quoting a History of the Republic of Nantucket published in 57 A.E. This in turn begins by stating that the Event is an insoluble mystery "...like time itself..." (p. 1) Thus, we are persuaded to accept the unexplained premise of the trilogy. It is a fair comment on life, anyone's life, that time is a mystery.
In the Prologue, our villain, Walker, sells guns to Agamemnon. The time travelers are changing not just history but mythology.