Col. Samantha Carter (Amanda Tapping) joins Dr. McKay (David Hewlett) and Dr. Keller (Jewel Staite) on a mission to convince the inhabitants of an off-world village rocked by frequent tremors, to move to a more stable part of the continent. But en route to the village, Dr. McKay plunges into a sinkhole, falling twenty feet to the bottom of a large subterranean chamber. Crawling to the edge of the rupture, Carter and Dr. Keller are relieved to see that McKay is unhurt. Suddenly, they feel the ground beneath them give way and they too drop out of sight. Realizing that they have fallen into a section of an old Genii mining facility they begin to search for a way out. But every attempt to escape the confines of the chamber seems to put them in further jeopardy, underscored by the constant tremors that shake their prison with ever greater force.