Ayeka and Mihishi are sweeping outside the shrine while Ryoko lays around. Sasami calls them to lunch when Ryo-Ohki runs up from a tomb. They all ask what it is when Katsuhito explains about the demon that fell to Earth 700 years ago. Ryoko wants to see the demon but the others overrule her. Later that night, when Tenchi comes home, Ryoko meets him and ties him up. She leads him into the cave to meet the demon.
Ryo-Ohki finds Tenchi's satchel and brings it home. Ayeka organizes a search party after she realizes that Ryoko is also missing.
Tenchi and Ryoko must battle against traps as the others get closer. Ryoko and Tenchi find the inner chamber and Ryoko starts to come on to him when the others arrive through the rock wall. Ayeka and Ryoko start fighting and they release the goblin...
...who turns out to be Washu, a mad scientist. She had been exiled to Earth many years ago. She sets up a labratory in a subscace chamber under Tenchi's stairs.