Billion x School FOD Original Story

In this spin-off drama, Class 0 is due to take a retake test. If they get the lowest class average in the grade, Kagami and Class Zero will be expelled! However, at that moment, Kagami unexpectedly says, "I don't have time to look after you guys." Even more, Class Zero also has Konno Naoto, who has the worst deviation score rankings. With Kagami telling them to "figure it out on their own," how will the students overcome this crisis on their own?
(Source: Japanese = Fuji TV || Translation = MulierNecis at MDL)