They had a doorway into the past. But it didn't just open on a specific place on a certain day. There was a sort of flutter, and it caused spatial drift and temporal spread. Two probes might go through together on the 21st-century side but come out miles and years apart on the Silurian side. So, when the second of two people going through a portal into the past is lost, the first feels an abstract guilt that eats into her pleasure at having traveled through time. This story is part of the author's brilliant Silurian Tales series. Download and start listening now!