OVA:

Ayeka and her half-brother, Yosho, were scheduled to be married. That all changed when Ryoko attacked Jurai and Yosho left looking for Ryoko, and never returned. Years later, while travelling through space looking for Yosho with her sister, Sasami, Ayeka comes across a wierd power reading emminating from the planet Earth. When she investigates, she finds non-other than Ryoko herself. Determined to find her half-brother, Ayeka captures Ryoko and the boy with her and questions them, only to find that the boy, Tenchi, is the descendent of Yosho, and that Yosho is probably dead. In an arrising turmoil between Ryoko and Ayeka, Ryoko makes both Ryo-U and Ryo-Ohki crash land and wrecks both of them. Now Ayeka and her sister are stuck on this planet, unable to continue the search for Yosho who may not be dead afterall.

Universe:

Ayeka is returning to Jurai from a wedding meeting on a distant planet, when she picks up a distress signal from the planet Earth. When she goes to investigate, she finds the person who sent the message was First-Class Detective Mihoshi, who was stranded on Earth. But, to Ayeka's suprise, she also finds her arch-nemesis, Ryoko. The insuing clash leads to a battle between Ayeka and Ryoko in space. Well both ships were destroyed, and Ayeka was stranded on the Earth. But, without Ayeka's presence in the Juraian royal society trouble starts to arise.

Shin-Tenchi (In Tokyo):

Ayeka and Sasami is on a hot pursuit of Ryoko and Washuu. They have stolen the Jurai power and Ayeka is determined to return it. Ayeka forces Ryoko and Washuu's ship down onto the planet Earth, where a foot chase insues. Ayeka traps Ryoko and Washuu, but Ryoko, out of desperation, uses the Jurai power on herself. Just then, Tenchi arrives on the scene. The crystals he wears on his neck are somehow activated, and he puts Ryoko out of commition. Ayeka retrieves the Jurai power. Ayeka decides to stay on planet Earth because of her growing affections for Tenchi, and is given one of the crystals Tenchi has as a symbol of friendship between herself and Tenchi. Months later, Tenchi goes to Tokyo to study causing issues between all the jealous women in the family.