The story tells the story of a collusion between Hong Kong police and criminals in 1973, under the instigation of the British, they embezzled huge profits and poisoned the citizens. The Governor of Hong Kong established the Independent Commission Against Corruption
On the eve of the election of the leader of Hong Kong's evil gang "Hong Le", Li Jing (played by Li Tianxiang), one of the leading candidates of "Hong Le", was kidnapped by the kidnappers, and threatened his wife Zhang Fei (played by He Peiyu) for 10 million. To redeem her husband. Zhang Fei asked the police for help, and the police station responsible for the case was the detective Lin Xiang (played by Deng Jianhong) who was undercover by Li Jing.
In McDull, the Alumni, our protagonist has grown up. He is no longer the little boy who banters with his mates at school. How he wishes he could just go on bantering all day long with his mates at the renowned Flower on the Spring Field Kindergarten. But that is not to be. Like all grown-ups, he has to grapple with harsh reality. McDull and his mates are scattered all over the place. Each one of them has to find his or her own path. In each of their hearts, they know they have failed. Meanwhile, life goes on in the kindergarten. Someone strums a guitar and the pupils chime in to the song: Puff the magic dragon, lives by the sea… A dragon lives forever, but not so little boys. With hindsight, McDull believes this could well be the maxim of the Flower on the Spring Field Kindergarten alumni.
Todo el equipo del inspector Wing, de la policía de Hong Kong, ha sido asesinado por la banda de Joe. Wing se convierte en un borracho hundido que se siente culpable por la muerte de sus amigos. Pero un oficial novato sacará a Wing del pozo y ambos empezarán la aventura para vengarse de Joe y de su banda de "Los Cinco".
Ming es un topo infiltrado en el departamento de policía. Se hizo policía a los 18 años siguiendo las órdenes del jefe de una sociedad secreta de carácter criminal. Por su parte, Yan es un topo de la policía infiltrado en la banda desde hace ya diez años. Ambos se sienten cada vez más atrapados en esos mundos a los que no pertenecen.