On opposite sides of the world, two female pilots, North Korean and Canadian, are given cryptic instructions. For Soo-jin, it is a mysterious mission that involves their old enemy; for Cynthia, it becomes a sleuthing exercise to determine what the North Koreans are up to. Through the cold months of winter, Soo-jin is ordered to travel to remote and secret locations for her mission training As spring emerges, both women grow more troubled as they independently begin to piece together the sinister purpose of the mission.

Soo-jin's exposure to new cultures erodes the conditioning imposed on her by her repressive regime as she travels through China, Canada, and into the United States of America. Her old notions of truth, enemy, and loyalty are overturned and she finds herself caught in a dilemma between her patriotism and her moral code. Cynthia does not fully understands the diabolical purpose of Soo-jin's role until the pair are on board an aircraft and its deadly cargo. It is high in the sky where the horror of the mission and its potentially devastating consequences becomes crystal clear.