Fourteen-year old Chikako and her best friend, Zak, rush out of school each day to look after ten-year old Hiroshi, while their dad is at work. When a pandemic strikes hard and fast, and the government announces a lockdown, Chika finds herself having to home-school her unhappy little brother, by herself. With her life thrown into turmoil, how can she deal with this added responsibility, maintain her own grades and stay close to Zak, whose keyworker parents are able to send him into school?