Richard Riddick (Vin Diesel) has a really bad rep and with good reason: Five years ago convicted killer Riddick escaped the galaxy's law enforcement during a botched interplanetary prison transfer and has been on the lam ever since. As The Chronicles of Riddick picks up our antagonist finds his relative freedom has been compromised when mercenaries out for the $1 million bounty on his head discover his location and hunt him down. Riddick escapes their clutches steals their ship and sets off for Planet Helion to find Imam (Keith David) the Muslim cleric he rescued in Pitch Black and the only person who could have squealed his location to authorities. But while Riddick's hunch about Imam are correct the cleric has a reason for luring the mammoth murderer out of hiding: Helion is falling to unholy armies of Necromongers--warriors who conquer by force in the vein of Star Trek's Borg. Of course Riddick doesn't give a damn about the Helions or their plight--until he gets wind that the Necromogers want to kill him because of an old prophecy that foresees their end at Riddick's hands. Like it or not Riddick is left with no other choice but to battle the Necromongers. The character of Riddick is unquestionably what made Pitch Black one of the most sequel-worthy sci-fi films in years. And Riddick would not have been one of sci-fi's most intoxicating characters if it weren't for Diesel. Like his Dominic Toretto in the 2001 actioner The Fast and the Furious Riddick is a villain of few words but when he speaks his carefully chosen words have impact--even if the dialogue is at times overly theatrical. Riddick is the perfect antihero; a cold-blooded and indifferent being who somehow evokes more compassion than the film's so-called good guys. Joining Riddick are some recurring characters including David as Imam but Riddick benefits the most from the addition of some new characters particularly Colm Feore as Lord Marshal the Necromonger leader whose goal is to rid the universe of all human life. Feore channeling nuggets of Julius Caesar into his role makes for one of Riddick's most thrilling foes. Another prominent addition to the cast is Judi Dench who has a surprisingly small role as Aereon an Elemental captured by the Necromongers and used for her special powers including ESP. Writer/director David Twohy took his horror pic Pitch Black which gained a cult following since it was released four years ago and managed to successfully turn it into an sci-fi actioner of epic proportions. Everything is grander here which is almost a given considering Twohy shot Pitch Black on a dime in Australia using colored filters. In Riddick the director distinguishes the film's different environments--the Necros' mothership Crematoria's cavernous prison and Helion--using warm to cool tones that are dazzling yet more subtle than its predecessor. The CGI effects get a little gamey at times but production designer Holger Gross' gargantuan sets are impressive and help craft Twohy's otherworldly vision into a plausible one. And although Twohy jumps genres from Pitch Black to its sequel his storyline evolves logically from the original premise. But while moviegoers unfamiliar with Pitch Black will be able to follow the story easily enough they may have a difficult time grasping what makes Riddick such a big deal; the film explains the legend but never fully captures its quintessence. This could hurt Riddick's chances to broaden its Pitch Black fan base.