Overview:
The dark untold story of Steins.Gate which leads with the bizarre madscientist Okabe, unable to recuperate from the failed effort at bettering Kurisu. He abandons his scientist that is lively alter ego and decides to give up, in pursuit to fail to remember the past. When all seems to be ordinary, he is apparently pulled back in to the last by fulfilling with an acquaintance of Kurisu, who tells him they have begun analyzing a system that stores the memory of an person anatomy and creates a simulation of these with their characteristics and characters. Okabe realizes and begins analyzing that the simulator of Kurisu has attracted back some unexpected tragedies that are new and anguish.
Zero is just a side story that explores events out of the Beta Attractor Field's long run which bring about making the finish of their original narrative possible.