Lionsgate has released the third and final trailer for their action-packed sequel The Expendables 3, following the character posters that debuted during Comic-Con last week. Barney Ross (Sylvester Stallone) is back with the rest of his mercenaries, as they go on their most dangerous mission yet, to rescue a group of younger Expendables from the nefarious Colonel Stonebanks (Mel Gibson), who co-founded the group years ago.Take a look at the latest footage which features new cast members such as Antonio Banderas, Wesley Snipes, Harrison Ford, Kellan Lutz and Ronda Rousey before director Patrick Hughes' action sequel hits theaters on August 15.In The Expendables 3, Barney (Sylvester Stallone), Christmas (Jason Statham) and the rest of the team come face-to-face with Conrad Stonebanks (Mel Gibson), who years ago co-founded The Expendables with Barney.