Evan arrives through a portal, after making a very stupid choice. Jo finds him in rough shape and helps out.
In which Jo and Evan, two survivors from an apocalyptic eldritch world, find one another in the overworld. Things don't start off well.
When Jo is AU'd into the Lovecraftian, Byzantine city of Yarnham, she becomes an addled, blood-drunk hunter clinging desperately to her humanity. Her drive to escape the nightmare pushes her to further and further depths, including turning on her ally, her last friend in the world.