Black Knight

Only 1% of the world's population was alive in 2071 due to poisonous air pollution, which had wreaked havoc on the planet. Gas masks are almost never used outside of the home, and deliverymen known as "knights" guard and deliver mail. Sa Wol, a teenage refugee with aspirations of becoming a knight, is introduced to one legendary knight, Knight 5-8. Knight 5-8 trains and guides Sa Wol with the assistance of Seol A, a Defense Intelligence Command officer, assisting him in realizing his dream in a harsh and dangerous environment.