Plot and cast from Wikipedia

Betrayed by the Necromongers and left for dead on a desolate planet, Riddick fights for survival against alien predators and becomes more powerful and dangerous than ever before. Soon bounty hunters from throughout the galaxy descend on Riddick only to find themselves pawns in his greater scheme for revenge. With his enemies right where he wants them, Riddick unleashes a vicious attack of vengeance before returning to his home planet of Furya to save it from destruction.

Vin Diesel as Richard B. Riddick
Jordi Mollà as Santana
Matt Nable as Boss Johns
Katee Sackhoff as Dahl
Dave Batista as Diaz
Bokeem Woodbine as Moss
Raoul Trujillo as Lockspur
Karl Urban as Lord Siberius Vaako
Alex Branson as Lex Branman
Keri Hilson and Antoinette Kalaj have also been cast in unspecified roles in the film.

Riddick website