Production on a fifth installment in Sylvester Stallone's 'Rambo' series will reportedly begin this September. Stallone is also currently working on the script for the movie, which picks up where 2008's fourth 'Rambo' film left off. The fifth movie is said to revolve around the former U.S. Army Special Forces soldier's attempt to rescue the daughter of one of his friends when she is kidnapped near the U.S.-Mexican border.