Chicago/Greenland 1959. Lucy Bledsoe works as a science writer for SIPRE, a Cold War research facility doing pioneering work on climate change. Lucy leads a double life as a closeted lesbian, having publicly sworn off women in order to take her job (government policies barred LGBTQ people from federal employment). But then she falls in love with Charlene, known as Charlie, and pretends to be straight as their romance heats up. SIPRE analyzes ice cores drilled at a remote American military outpost, Camp Century. The camp is built entirely under the Greenland Ice Sheet, powered by a portable nuclear reactor. When Lucy exposes dangerous problems at the camp, including radiation leaking from the reactor, she risks losing her life, her job and her secret lover.

Inspired by real events, the script is adapted from A Thin Bright Line by Lucy Bledsoe.