Yuu commands an interstellar crime force dedicated to eradicating space piracy, leading a core team comprising Saya, a tanuki motorcycle robot known as Momo, and a feline operative named Nyan. As a premier Cosmic Hunter in the galaxy, he safeguards space freighters and neutralizes interstellar threats. His unwavering duty interrupts a personal date with Saya when ally Nyan transmits a distress signal, coinciding with pirate Belga’s calculated attacks to provoke Yuu into direct combat.

Adversarial encounters occasionally entangle personal complexities, exemplified when space pirate Berga develops romantic feelings for him. Yuu’s rejection of her advances intensifies her hostility, escalating her destructive campaigns across the stars.

In subsequent operations, Yuu voyages 25 years into the past via time machine to dismantle pirate Gardo’s conspiracy. Gardo seeks to annihilate Daigo—future founder of the Cosmic Crime Force (CSC)—to prevent the organization’s inception. During this temporal mission, Yuu confronts younger incarnations of his allies and thwarts Gardo’s scheme, unearthing a pivotal revelation about his own ties to individuals like Rei and Mai.

Later, Yuu accepts a rescue assignment on planet Kazarin after Princess Sarria’s abduction. Exploiting Saya’s uncanny resemblance to the princess, he deploys her as Sarria’s decoy while scouring for the captive royal. This operation exposes a deeper, more treacherous conspiracy lurking beneath the surface.