In a brutal war for the Solar System, Earthlings destroy almost all enemy ships equipped with independent time generators. After uncovering a network of alien spies on Earth and successfully repelling a coup, they celebrate their victory. The threat of the Solar System being taken over by invaders from the Galactic core has passed.
However, the scouts of the special unit “Invisible” receive information from a race of alien scientists that in a remote part of the galaxy there is a secret system where work is being done to recreate engines capable of piercing time. The work is nearing completion. If the aggressors are allowed to finish it, then the zags will be able to equip their enormous invasion fleet with super-time engines—and then Earth, a tiny planet on the edge of the Galaxy, will no longer be saved by anything. Meanwhile, on Earth, a new enemy is discovered—one capable of putting not only peace in the Solar System at risk, but also of upsetting the balance of power in the Galaxy.