Tenchi Masaki is the unlikely hero of our story. He was just a normal seventeen year old boy. Until THEY showed up. A group of alien women that included everything from princesses to a space pirate to a mad scientist to police officers. Then Tenchi discovers his own uniqueness. And life has never been the same.
OVA
Tenchi was always curious about what was in the cave behind the Masaki shrine. He seizes the chance to take a look the second he gets it. And he ends up with more than he bargained for. Tenchi awakens Ryoko, the space pirate, from her long sleep. Aside from her trying to kill him the first time she sees him again she also decides to move in with him. And others follow after her. Poor Tenchi just wants some peace and quiet.
Tenchi Universe
It was just a normal day for Tenchi. On his way to school he witnessed two strange objects fall from the sky. Inside one wreckage he finds Ryoko, and later Mihoshi from the other. Stranded, they both must stay at Tenchi's home. And they don't leave when others come looking for them. Every rescue seems to end up stranded at the house one way or another.
Tenchi in Tokyo
Tenchi decides it is time for him to leave home. He moves to Tokyo and begins to go to school there. Though they talk often the others are going crazy without him home. Jelousy also comes between them when Sakuya appears. A young girl from Tokyo who sets her heart on Tenchi. Could one girl and a few hundred miles really tear the family appart?