Although this TV series was released after the Tenchi Muyo OAVs, everything is different. Tenchi Universe is like an alternative version of the whole Tenchi saga. Several girls coming from different parts of the galaxy somehow manage to squeeze themselves into Tenchi’s once ordinary life. There’s Ryoko, the notorious space pirate; Aeka, the first princess of the planet Jurai; Mihoshi and Kiyone, a pair of bumbling space detectives… add a crazy scientist, another alien princess, some menacing enemies and you’ve got a madcap and adventure-filled series that is Tenchi Universe. But what’s this? It looks like Tenchi himself is decended from alien royalty too!
Descriptions taken from AniDB.net