Timeshaft by Stewart Bint
Approx. 55,110 words.
Published on May 11, 2013.
The Timeshaft is a path through time from pre-history to the end of the world, under the control of environmental protection group WorldSave.
Its operatives travel through the Timeshaft preventing ecological disasters, but that's more of the back story. The plot focuses on leading agent Ashday's Child. What is his hidden agenda, why has he really spent his life flitting through the ages?