Icebreaker by Steven William Hannah 

SPSFC 2023

Inside their walls, the people are safe from exposure to the unnamed horror that broke the world long ago; but now Bear, the last scientist in Forgehead, takes a case that threatens to throw that safety into question. Someone has been terminally exposed to the phenomenon, despite never having ventured outside the walls. This has only happened once before - to Bear's father. With the safety of Forgehead in question, and an opportunity to finally discover what happened to his father, Bear must leave the safety of the walls to unravel the mysteries left behind by the pre-cataclysm world; a task that will require him to join the Interloper Initiative, the team who crew the gigantic Crawler landships, the only vehicles that can roam the world outside the walls in relative safety. "Icebreaker" is the first entry in the Interloper Trilogy, a tale of horror and science charting the last days of a dying world, and humanity's endeavour to survive.