After I read the first volume of the Chronicles of St. Mary's, I noticed that the audible version of this (and a few others) were free. They still are and you might want to try them.
It is entirely possible to listen or read this short story (its about 30 minutes in audio) without having read volume one of the series. The info dump is not long and serves simply to make time travel understandable. In short, certain members of St Mary's travel back and in time and learn a little something.
Mary Beard would like this story, to say anything more than that would ruin it.