Sleeping Dogs tells the story of Wei Shen, a Hong Kong-American detective who goes deep undercover to infiltrate the notorious Sun On Yee triad in a gritty, open-world Hong Kong, balancing his police duties with the violent criminal life, all while seeking revenge for his sister's death linked to the gang. Players navigate moral dilemmas as Wei rises through the ranks, caught between his cop identity and his criminal past, culminating in a brutal struggle for control within the triad and a confrontation with its leaders.