Descending into ID

Ravina, the overseer of the group who has gone to the polar ice to build a weather station discovers a hole in the ice with parallel sides. Descending the tunnel she sees a black dot in the ice. It follows her every move. The black dot grows into a face. The eyes stare at her. Before she could react an arc of electricity engulfs her. She manages to push the ascent button just before she is struck with a second arc. Her colleagues save her life. Josh, Florian, and Clay, are summoned. Due to the fact Henry's scans are being blocked by something under the ice someone has to descend the tunnel. What species will they find in ID? Will they be friends or enemies? Above all else what's the reason behind why they live underground?