Change is in the air as Tess Fontana picks up the reins at Global, leaving little time to spend with Carter. Zoe, inspired by helping deliver Allison's baby, takes a Eureka-fied aptitude test to help guide her choice to pursue medicine, and is told that she should pursue robotics. Zoe's disappointed, but Lucas is thrilled. Would that have anything to do with him wanting her to join him at M.I.T.?
Meanwhile, Carter and Lupo oversee traffic control for a special delivery by truck- a very long truck. Inside is an ice core drilled from the Arctic, brought in by Zane and the project leader, Taggart, back from a year-long walkabout. Lupo finds Zane strangely cold, and suspects he's jealous about her unresolved relationship with Taggart. The ice core causes trouble for Tess, too. Because it came from Russian ice, no one can study it until Chief Security Officer Yuri Gregor signs the paperwork. Gregor demands an overwhelming amount of documentation before signing. As Gregor stalls, Carter suspects an ulterior motive. When Carter goes to take ice core measurements for Yuri in a special cold lab, he finds ice covering everything, including Taggart. Tess wonders if Zane's new refrigeration units might be malfunctioning but Taggart fears something much more sinister. Everyone entering the cold lab wears full Arctic gear, except Zane, who wears PetroTech, a reactive thermal barrier that insulates all the buildings in Eureka. It seems to offer him immunity to the numbing cold surrounding the ice core.
After Taggart's narrow escape, Carter insists they test Zane's cooling units. Taggart reports they are functioning perfectly but he notices inexplicable striations in the core itself. Then it becomes clear that Zane's behavior has a physical cause. Unless the enigmatic Gregor signs the authorization papers soon, Zane may freeze to death. And not just Zane... the ice is spreading and threatens to envelope the entire town- and beyond.