In the underground world of illegal mahjong, what does it take to be No. 1? K (Goki Maeda) is a high school student who gets pulled into the dangerous world by a man known as Seki (Satoshi Ichijo).

K, a high school student, has challenged to a high-stakes illegal mahjong and is now in trouble. He was hiding a foreign girl named Amina in his house. K had to enter the world of dark Majong to protect Amina but he also tastes the exciting thrills of the game.—Amazon Prime Video