"Mala" is short for "malavita", formed by "mala" and "vita", literally "dishonest life".
This is a synonym of "criminalità", "Crime" (properly intended as "criminality"), "local mobsters".
The verb "ordinare" can mean "to give orders", "to rule", "to be in charge".
So, "la Mala ordina" means "Crime is in charge", "local mobsters rule", but with a particular nuance, you would expect the sentence to be completed with the actual orders. In fact, normally, if you want to say that someone is in charge, someone rules, without further explanations, you would use the verb "comandare", not "ordinare". The fact that they used "ordinare" suggests that some actual orders have been given but these are intentionally omitted in the sentence (ordina cosa? What orders do they give?) - perhaps because you are supposed to find out while you watch the movie? Or perhaps you are supposed to complete the sentence by yourself, "if they give an order, whatever the order is, the order must be followed"?
Note that sometimes "mala" is used as synonym of mafia, organised crime (in the '70s/'80s "la Mala del Brenta" was famous, Felice Maniero's "Venetian mafia").