Watch Martial Law II: Undercover for Free: How to Stream the Movie Online at 123Movies. . Sean and Billie are undercover cops and martial arts masters. Investigating the death of a cop, they uncover a deadly ring of murder and corruption at a glitzy nightclub where the rich are entertained by seductive women and protected by martial arts experts. Billie goes undercover to infiltrate the crime ring, leading to an explosive finale.