Rock 24 takes place on an abandoned Cliffside prison. The prison is situated on the side of a sheer cliff face meaning the only real way in and out is by air. The combine have moved in to the facility and are re-using it as a place to hold rebel leaders and other important Rebels. Gordon is required to infiltrate, free the Rebel leader and hopefully escape from the facility alive. Unfortunately the prison is rapidly deteriorating around him and there isn't much time. Rock24 was in production for 9 months as a spare time personal project by two guys who work in the games industry. This is their first mod and attempt at level design.
This review may contain spoilers
So far, this is the best overall mod I have played. Whereas other mods have just one or two strong suits, such as Awakening's music or City 7's voice acting(to an extent), this one combines them all in a well designed, hour and a half game. The puzzles are challenging to a degree where they are still hard, but not so much as to make me pull out my hair. Voice acting is one of the best I've heard, apart from a few pronuciation errors(It's pronounced MAY-sah, not MEH-sah. Got it, Dr. Newell?). The storyline pushes you to see the game through to the end, and the gameplay keeps you entertained throughout its length. No Half-Life 2 fan in his or her right mind should pass up this mod.