Line Walker (2016)

Several cops went undercover. Due to some issues, all undercover identities were wiped clean from the police database.

When undercover agent Ding receives an encrypted message from Blackjack, who claims to be an undercover agent that has lost contact with the police, she reports it to her superior officer Inspector Q, who immediately launches a mission to search for Blackjack. While Inspector Q narrows down Blackjack's whereabouts, he learns of a finance group's involvement in a drug deal in Brazil which involves company chairman Kwok Ming, his advisor Lam, Lam's right-hand man Shiu and the supposedly dead triad leader Foon-hei, who is surprisingly alive and kicking, and is plotting a comeback to the crime world.