In a fierce battle for the Solar System, earthlings destroy almost all enemy ships equipped with an independent time generator. Having uncovered a network of alien spies on Earth and successfully repelled the Zag invasion, they celebrate their victory. The threat of the capture of the solar system by invaders from the galactic core has passed. However, intelligence officers of the Invisibles special forces receive information from a race of alien scientists that in a remote part of the galaxy there is a secret system on which work is underway to recreate engines capable of piercing time. The work is close to completion. If the aggressors are allowed to finish them, then the Zags will be able to equip their huge invasion fleet with super-temporal engines, and then nothing will save Earth, a tiny planet on the outskirts of the Galaxy. Meanwhile, a new enemy is discovered on Earth, which is capable of threatening not only the world in solar system, but also upset the balance of power in the Galaxy.