Tenchi Masaki gets the surprise of his life when a teenage girl approaches him and calls him "Daddy." Believing that the girl is mistaking him for someone else, Tenchi brings her home to figure out what is going on, which turns out to be a big mistake. When the girl introduces herself as Mayuka Masaki, Tenchi's daughter, the Masaki household is thrown into yet another frenzy. Thinking that Mayuka is just taking advantage of Tenchi, the girls refuse to believe that she is really his child. However, when DNA testing reveals that Tenchi is indeed her father, Washuu comes to the conclusion that Mayuka is his daughter from the future, the result of a recent time distortion. With this new revelation, everyone tries to welcome Mayuka into their lives with the sole exception being Ryouko Hakubi, who senses something sinister lurking beneath Mayuka's charm. Startica is the Summer Festival on Jurai. Many years ago, Tenchi's grandfather, Yosho, met a young girl during Startica and just as their relationship blossomed, she was attacked by the Jurai Palace who revealed that the girl was Yuzuha - the Demon of Darkness!Wounded by the attack, Yuzuha fled, but many years later her feeling of betrayal lead her to plan her revenge by taking Yosho's only grandson; Tenchi!On a hot summer day, a fetching young girl named Mayuka appears to Tenchi, calling him Daddy! Jealousy and envy follow as Ryoko and Ayeka battle for Tenchi's attention with an apparently new rival. Who could the mother be?!Sasami befriends Mayuka as they compare Earth's Christmas and Jurai's Startica celebrations and Mayuka is welcomed into the Masaki household.However, Mayuka is just a puppet of the Demon, Yuzuha, and it's her plan to bring Tenchi to the Nightmare World completing her revenge! Will Tenchi be able to resist Mayuka's love? Can Sasami convince Mayuka to change?It's a battle for Mayuka as she chooses between her parents; Tenchi and Yuzuha! To be the Daughter of Light or the Daughter of Darkness!