In this episode we meet Tenchi Masaki who appears to be just your average Japanese teenager. He is a hard working boy who attends the local high school. We find out that Tenchi also helps his grandfather at the family shrine as well as train with his grandfather in sword fighting.
Close to the Masaki shrine lies a cave that is enclosed by an iron gate. Within this cave legend has it that a demon is imprisoned there after being defeated by an ancestor of Tenchi's by the name of Yousho. The sword that Yousho defeated the demon with is also located in the cave. Tenchi's grandfather possesses the key to the gate, and the only way Tenchi can get the key is to take it from him. One day through either luck or his grandfather's design, Tenchi manages to possess the key, and with it he enters the cave.
Within the cave he finds the legendary sword. The sword that can supposedly cut through stone appears rather worn, and Tenchi in disappointment smashes the rusted blade against a stone, not knowing that this stone is the seal to the demon. A passage opens up to where the demon rests, and Tenchi falls through the entrance of the passage. He lands in a large cavern with a light emanating from the middle. As Tenchi inspects closer, he finds that the demon is real appears to be a mummy. Tenchi then flees the room through the same way he got in, and puts the broken stone seal together. The passage to the demon then closes up, and Tenchi, believing he had successfully kept the demon from escaping, leaves the cave.
The next day after school Tenchi feels a presence and follows it up to the roof, where he encounters the demon! The "demon",
however, no longer had the body of a mummy but that of a young woman. The woman introduces herself as Ryouko, and she states that she
is very angry at having been imprisoned. "I just want to let out my anger...now!", she announces and then proceeds to attack Tenchi! Tenchi
is then chased throughout the deserted school building, but it seems he can not escape from Ryouko, who has the power to teleport and pass
through walls. Worst yet, she can even fire energy bolts from her hands! One of the bolts hits a gas pipe, and another blast ignites it, thus
causing a massive fire. Tenchi then faces off with her with the old sword he got from the cave. To his surprise, an energy blade appears where
the old rusted blade once was. The sword then seems to take a life of its own, and eventually Tenchi makes Ryouko submit. Ryouko acknowledges defeat
and disappears from sight. With the school in ruins and sirens screaming in the distance, Tenchi has no choice but to return home.
Upon entering his room, an exhausted Tenchi falls upon his bed. However, it turns out that someone is sleeping under the covers, and as Tenchi pulls back the covers, who does it turn out to be but Ryouko. Thus Tenchi's normal life begins to end with the arrival of the first of his soon-to-be close friends.