The Zemurian continent's largest jaeger corps, the Northern Jaegers, are guarding relief supplies headed to Haliask, North Ambria, when they spot a village being attacked by monsters. Lavian, a petite, quiet jaeger defies orders to help the villagers.

The Empire scouting squad finds itself in hot springs paradise Ymir, where they encounter a phenomenon that has turned the hot springs cold. Lavian and Iseria investigate, but Iseria ends up trapped in freezing conditions. Lavian must try to free her with the limited options at her disposal.