A scientist named Doctor Clay is tasked by the superdimensional being Tokimi to bring Washu to her. To do this, he and his robotic assistant Zero go to Earth and abduct Ryoko, with Zero duplicating and assuming Ryoko's form so that she can infiltrate the Masaki household incognito and capture Washu. However, "Zero Ryoko" struggles to accomplish her mission due to being repeatedly distracted by Tenchi, as she inherited Ryoko's feelings for him.
Plot
Dr. Clay and his assistant Zero scavenge through some space debris and find traces of Washu. They give this report to their superior D3 and his superior lady Tokimi. Lady Tokimi orders Dr. Clay to retrieve Washu and so he sends his assistant Zero to do the job. Immediately after arriving on Earth by the Misaki residence, Zero captures, takes the form of Ryoko, and takes her jewel as well. Meanwhile, Tenchi is once again being experimented on by Washu, concerning his use of the Light Hawk Wings. This continues until Sasami arrives to inform the two about dinner being ready. Upon arriving at the Masaki household, Zero is meet by Tenchi, which makes her feel flustered. The following day, Mihoshi receives new orders from Galaxy Police HQ involving a space robbery. Back to Zero who has failed many times in attempting to capture Washu, Dr. Clay orders Zero to assassinate Tenchi. This is because Tenchi is a major distraction to her for her being able to complete her primary mission. Although reluctant, Zero obeys and while Tenchi's sleeping, he goes into his room to assassinate him.