Jeremiah is set in a future post-apocalyptic world where, almost a decade before, a deadly virus wiped out the world's adult population sparing only those who haven't reached puberty. Now in their 20s, the oldest survivors of the pandemic include Jeremiah and the colorful but cynical Kurdy. Jeremiah is on a personal quest to relocate a mysterious place called Valhalla, which his father claimed might hold some hope for the survivors. As Jeremiah falls into a reluctant partnership with Kurdy, both explore new areas and encounter other groups of young adults who are divided into rival social groups. In the course of the season opener, Jeremiah's smaller personal quest is redirected when he discovers a group of highly organized survivors who want to enlist him to orchestrate peace among the warring factions and to try and prevent the killer virus from returning.