"Ghost in the Shell" is the name of a media franchise that started back in 1989 as a manga series. The manga was first adapted into several movies with the first one being released in 1995. The first animated series started airing in 2002. Video games have also been released for this franchise.
The events of the "Ghost in the Shell" movie take place in future Japan, where this country dominates the world's affairs after 2 more world wars take place. Japan is not alone in ruling the world, it is part of an alliance. To keep its supremacy, this alliance uses highly advanced technology.
This technology is seen through cybernetically augmented agents that can download their consciousness into the internet and hack machines and even the new human/machine breed.
In this movie, Major Motoko Kusanagi is one such agent. She tries to catch the virtual entity known as the Puppet Master who gained consciousness and requested political asylum as well as true physical existence in defiance of its creators.