It is the end of Tenchi’s first week in Tokyo, and it is clear he hasn’t quite got the hang of cooking for himself- at least if his burnt attempt at Sunday breakfast is anything to go by.
Meanwhile, in the depths of the crystal palace, something more sinister is going on. The blonde girl has summoned three deputies into existence, and it seems certain that can only spell trouble for Tenchi.
Back at the apartment, Tenchi is surprised to receive an early morning visitor- Sakuya. She wants to spend the day showing him around Tokyo, but before that, she even brought breakfast- ready meals from five different convenience stores. Given his earlier attempts at feeding himself, Tenchi is more than happy to taste something edible.
The blanket is not quite fully folded over the dimensional tunnel, and naturally Ryoko and Ayeka have been spying through the crack. When they see Sakuya so close to Tenchi, they call through the tunnel to warn her off. Tenchi quickly explains away the noise as the neighbours’ television, and decides that it would be a good time to leave the apartment.
Despite Washu’s insistence that the girls cannot open the tunnel from their side, Ryoko decides to give it a try anyway- by blasting it with her full power. Unfortunately, her plan quite literally backfires, shaking up the whole house, and completely draining Ryoko of energy. Even this setback cannot stop Ayeka and Ryoko for long, however, and soon they are once again trying to force open the tunnel by poking cutlery through the crack.
When the next plan fails as well, the girls seem ready to give up, at least until they spot Ryo-Ohki. What better candidate to slip through the crack and open the tunnel from the other side than the little cabbit? Against her will, poor Ryo-Ohki is shoved through the crack, only to get stuck halfway.
Whilst Ryoko and Ayeka continue trying to push poor Ryo-Ohki through the crack, Tenchi spends a pleasant morning seeing the sights with Sakuya. But as they take a shortcut through one part of town, the couple find themselves caught in a mysterious fog. Looming out of the fog is a huge and mysterious mansion, and Sakuya is eager to check out it. As she pushes open the door to see inside, Tenchi reluctantly follows- but when they get inside, the door blows shut behind them.
As they try to push open the door, the owner of the house appears and introduces himself. His name is Hotsuma, and although Tenchi and Sakuya do not know it, he is one of the three servants of evil summoned in the crystal palace. He tells the couple that this is the House of the Eternal Pledge, and invites them to a party he has arranged for the afternoon.
Tenchi is reluctant to stay, but Sakuya seems entranced by the idea of a party, and eagerly follows after Hotsuma. As they follow their host, Hotsuma relates the history of his mansion. Long ago, it was owned by a nobleman whose daughter fell in love with a lowly servant. Knowing that they could never be together, the two swore their eternal love in the house, before committing suicide. Now, numerous lovers journey to the house so that they too can make an eternal pledge, but only those who are destined to be together forever can ever reach their destination.
Finishing his story, Hotsuma bids Tenchi and Sakuya a temporary farewell, and as he does so, two doors beside them open, pulling the couple apart and into a strange blue nexus.
Meanwhile, Ryoko and Ayeka have been pushing hard on the stuck Ryo-Ohki, so much so that her bottom is now red and sore. Unwilling to give up so close to their goal, Ayeka reveals her failsafe- a spork. She shoves it into Ryo-Ohki’s backside, causing the poor cabbit to finally burst through the crack, propelled by sheer pain. Now on the other side, Ryo-Ohki is able to pull back the blanket, letting Ryoko and Ayeka through to Tokyo.
In short order, Ryoko and Ayeka get Ryo-Ohki to track Tenchi for them, and soon they are following his trail throughout Tokyo, eventually making their way to the fog that surrounds the House of the Eternal Pledge.
Still stuck in the house, Tenchi finds that not only has he been transported to a chapel, but he is now dressed as a groom. Soon after, he is joined by both Sakuya and Hotsuma, dressed as a bride and priest respectively. Hotsuma explains that the party he mentioned earlier was to celebrate their wedding- being able to find the House of the Eternal Pledge indicates that Tenchi and Sakuya are meant to be together, and now it is time for them to seal that bond by pledging their eternal love.
Having apparently fallen under the house’s spell, Sakuya eagerly affirms her feelings for Tenchi when Hotsuma asks her to pledge her love. Turning to Tenchi, Hotsuma asks the same question, but Tenchi isn’t quite ready to commit to a girl he only just me.! Hotsuma quickly turns a hypnotic gaze on Tenchi, and as the young man falls under the spell, he too begins to recite the words of his own pledge.
Having reached the mansion, Ryoko and Ayeka are eager to get inside, but the door is locked, and even phasing through it proves impossible. Finally, Ryoko fires an energy blast at the door, knocking it down and leading them straight to the chapel.
Ayeka and Ryoko’s arrival jolts Tenchi out of the hypnotic effect of the spell, forcing Hotsuma to change tactics. He quickly takes Sakuya hostage, much to Tenchi’s distress and the others’ indifference. Despite Ryoko and Ayeka’s refusal to help, Tenchi charges in to save Sakuya. Hotsuma blocks his blow and throws him aside- and when Ryoko and Ayeka see their beloved Tenchi hurt, they are quick to jump into action. Tossing Sakuya away, Hotsuma fires an energy blast, which Ayeka quickly blocks. Ryoko quickly goes on the attack, only to discover that she and Hostuma possess similar abilities, and are pretty much evenly matched.
Whilst Sakuya, Tenchi and Ayeka watch from below, Ryoko and Hotsuma trade blows, eventually blasting their way out to the roof. Impressed by his adversary, Hotsuma asks Ryoko to tell him her name, and after mutual introductions are made, he tells Ryoko that, although he must leave now, the two of them will meet again to settle the score between them. So saying, Hotsuma teleports away, and as he goes, the House of the Eternal Pledge disappears as well.
To Tenchi’s surprise, Sakuya is not distressed at Ryoko and Ayeka’s display of special powers- in fact, she is almost star struck. Quickly thinking up a cover story, Tenchi tells Sakuya that his friends are secret agents working for a group called ‘Monster Busters’. The story sounds a little pathetic, but Sakuya accepts it wholeheartedly, thanks the ‘Monster Busters’ for coming to rescue her, and even asks for their autographs! It may seem a little strange, but at least, for the moment, no one is fighting.