Cygnus marks a shift in the Barry Short adventure novels. The series has explored the past through archeological finds until in Cygnus the present comes crashing through when an Unidentified Flying Object emerges from an isolated lake near a French resort town where Barry and his friends are vacationing. Questions abound along with scant evidence. Was the object real or a confabulation of the mind? Did Etienne fall asleep in the woodlands or did he experience what ufologists call "missing time"? Could the lightning storm that sets fire to a Swiss mountaintop observatory actually have been an attack? And if it was an attack, by whom and why? Mixed in with the mystery is a suggestive passage from Dante that melds present with past by linking The Purgatorio's account of "The Angel Boatman" with contemporary reports of UFOs. Could Dante's narrative have been modeled after an authentic observation? And if it was, how could such phenomena have been misunderstood for so long? Or is it known by a privileged few like Roland, a scientist with a highly unusual pedigree and secondary occupation, who is called in to investigate but has agendas of his own. In the midst of this otherworldly scenario, life continues on planet Earth where Summer must make complicated choices when she finds herself torn between a life of tradition and a life of adventure.