Supersonic Fingers is the first Gunnm Gaiden story, it takes place shortly after Gally's fight with Jashugan. Gally is attacked by an unknown sniper, and while she recouperates, her hunter-warrior friends search for the culprit. The culprit is a strong fighter with a death wish that only Gally can fufill. The Holy Knight is the second Gunnm Gaiden story, Homecoming is the third, but takes places immediately before The Holy Knight. Before he met Gally, Ido worked as a hunter-warrior to make ends meet. Although a skilled doctor, he had no skill in the areas of cybernetics. He saves and befriends a young, mysterious girl, whom he names Carol. During their time together Ido learns the art of cyber-medicine, and starts his cyber-doc practice, but Carol's past catches up with her and Ido learns a painful lesson about medicine(https://kodansha.us/series/battle-angel-alita-holy-night/)