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? Hiding in the background, Yuzuha, the Demoness of Darkness, is about to get her revenge against Yosho for a grudge held over 700 years! She begins her plan by using Mayuka to steal Tenchi away to the dimension of Darkness. So it begins again, Tenchi must fight to save his friends and Mayuka, daughter or not!