The story of "Perimeter: Emperor's Testament" (add-on for "Perimeter") opens new pages in the Exodus history. Whereas the Spirits are on the way to their destination and the Harkbacks are seeking the mythical Earth, the Emperor builds up his Sponge Empire using automatic bases - his Vice Frames. He creates the Mechanical Spirit to help him discover new Worlds. One of the Vice frames starts the testing of this mechanism, this leads to appearance of the super mind - Mechanical Messiah and the discovery of the parallel Chain of the Psycho-sphere Worlds. We also meet the "lost" Exodus Frames and find traces of the mysterious alien race. The sides are in the middle of the deadly battle - who wins? The player will find out the answer during 25 missions of the Single Player campaign.

Aside from the extraordinary story, "Perimeter: Emperor's Testament" features new graphics, new buildings and units and a brand new soundtrack. The game also features 3 brand new multiplayer maps.