From Collider.com, here is the synopsis that went out with recent casting notices for Captain America: Civil War, the upcoming Marvel Studios adaptation of the 2006-2007 crossover comic storyline "Civil War" and what has been frequently referred to as "Avengers 2.5":
http://collider.com/captain-america-civil-war-filming-date/
http://collider.com/captain-america-civil-war-filming-date/
Captain America: Civil War is slated to begin shooting on the 1st of April 2015 and is due out for release in theaters on the 6th of May 2016.Following the events of Age of Ultron, the collective governments of the world pass an act designed to regulate all superhuman activity. This polarizes opinion amongst the Avengers, causing two factions to side with Iron Man or Captain America, which causes an epic battle between former allies.