Eighteen-year-old Tsukasa Mizugaki has failed his college entrance exams, but after pulling some strings, he manages to land a job at the Sion Artificial Intelligence Corporation. SAI Corp is responsible for the creation of "Giftias"—highly advanced androids which are almost indiscernible from normal humans. However, unlike humans, Giftias have a maximum lifespan of 81,920 hours, or around nine years and four months....