splintercell splits the 1pl with the double agent. chaos theory is about an terrorist group that steals all the power supply in usa, the reason is that usa won't know that they are planing to attack them with big missiles. later usa get's bomb by an missile on a marine ship. usa suspect a country and sam fisher must find out who it was. you'll go trough many cool levels who get's harder as you progress and must fight against a heavy armed soldiers witch has nightvision googles like you soo you can't hide from them in the dark. chaos theory also has coop play. this features is nicely done and very funn, but some levels can have a lack of this to do and some has ridicules goals, but it's a MUST BUY. specially for those who has not played the game before