Riki and Iason exist in a system designed to destroy what they have, and the show knows the relationship is poison before you do. The sci-fi scaffolding isn't window dressing, it's the cage they're trapped in, and every moment of tenderness is an act of defiance against a hierarchical world that forbids it. By the end of two episodes, you've watched a love story that costs everything, and you understand why he stays.
In Tanagura, the computer-run capital of the planet Amoi, hair color fixes a person's place. Blondies form the ruling elite, while darker-haired people are dismissed as "mongrels" and rarely escape the slums. Blondies keep young boys as pets for a few years, and they are not meant to hold on to them for long. Riki, once the leader of the slum gang Bison, was taken from Ceres and made the pet of the Blondie Iason Mink. Iason has kept him for years despite the disapproval of Jupiter, the supercomputer that rules Amoi, and rumors say the two sleep together. Now Riki has returned to Bison and to Gai, his former friend and lover. He is torn between resisting Iason's obsession and giving in to it, while someone is always willing to betray him.