Shootouts and car chases are interrupted only by brief bouts of middling melodrama in “The White Storm 2: Drug Lords,” an in-name-only sequel to the 2013 hit about cops involved in the war on drugs. Vigorously directed by prolific veteran Herman Yau (“Shock Wave”) and well served by an all-star cast headed by Andy Lau and Louis Koo, this Hong Kong action-thriller isn’t deep but is certainly not dull. Mainland audiences have gone wild for “Drug Lords,” with 1.8 million admissions and a $105 million gross in 7 days since its July 5 release, which suggests the potential for relatively strong returns in the U.S., U.K. and other territories as well. Hong Kong release is set for July 16.

In an extended 2004-set prologue, Tin (Lau) and Dizang are low-level hoods working for Tin’s uncle, Yu Nam (Kent Cheng), a triad boss with a strict “no selling drugs” policy. When Dizang breaks the rule,...