Subtle themes include religion, which runs through the film, as Yong Soo hopes that his son comes back safely, as well as football which is a way in connecting the North Koreans to the outside world.

A North Korean father and husband decides to illegally cross into China to buy medicine for his pregnant wife, who is suffering from tuberculosis.

He starts working as an illegal immigrant under the constant threat of capture by Chinese authorities and deportation back to North Korea.

He argued that the film was written on a screenplay titled "The Conditions of Human" based on the story of North Korean defector Yoo Sang-joon which he wrote.

Vantage Holdings, the distributor of Crossing has countered the accusation by saying that the director nor the film company has not violated Lee's copyright and added that they are looking into taking legal measures themselves.