Eighteen-year-old Tsukasa Mizugaki failed his college entrance exams, but after pulling some strings, he manages to secure a position at the Sion Artificial Intelligence Corporation. SAI Corp is responsible for creating "Giftias"—highly advanced androids that are nearly indistinguishable from ordinary humans. However, unlike humans, Giftias have a maximum lifespan of 81,920 hours, or roughly nine years and four months. Terminal Service One, the unit to which Tsukasa is assigned, handles the collection of Giftias that have reached their expiration date, before they lose their memories and turn hostile. Shortly after joining Terminal Service One, Tsukasa is paired with a beautiful Giftia named Isla. She is a veteran of the Terminal Service and regarded as the best at Giftia retrievals, despite her petite figure and calm demeanor. Time is fleeting, though, and Tsukasa must come to terms with his feelings for Isla before her time runs out. No matter how much someone desires it, nothing lasts forever.