Nagi is a bounty hunter with a fierce reputation who has lost but one target in her distinguished career — the space pirate Ryoko — and wishes to wipe that blemish off an otherwise perfect record.
Traveling with her cabbit Ken-Ohki, Nagi makes a living hunting down wanted criminals in the galaxy. So far, she has only one quarry to have eluded her - Ryoko. She had tracked the space pirate to Earth, where she had taken Tenchi Masaki hostage, thinking he and Ryoko were lovers.
Originally, the two were to fight in space, but a complication occurred, Ken-Ohki and Ryo-Ohki had fallen in love and would not fire upon each other. So a "wild west" setting was created by Washu on the planet Venus so that the two would fight it out. It ended with Ryoko about to kill Nagi, but the cabbits intervened; Ken-Ohki threatening to fight and Ryo-Ohki begging her to spare Nagi. So Ryoko released the bounty hunter.