The Charons are tour guides in a world traversed by a deep fissure of gigantic proportions. Within this fissure, known as the Acheron, all manner of dangers lie in wait for travelers. Nature is merciless, and vast swathes of the landscape are inhabited by eerie creatures. Nothing there is as it seems. Charon number 78 is a taciturn loner who seems to harbor a few secrets, yet has his heart in the right place. And anyone who lets him guide them through Acheron can be sure that Charon 78 will do everything in his power to bring his clients safely to the other side.