Shy ninja

"Eleven-year-old Rena suffers from social anxiety disorder. It keeps her from engaging at school, hanging out with her best friend in person, or participating in any sort of group activity. But when, on a dare, she enrolls in a fake-sounding 'school for ninjas,' she quickly learns it's no joke! Immediately, Rena's caught up in an ancient prophecy--that she will become the ninja master known as 'The Ghost'! Assuming she can conquer her own anxieties, will Rena help her instructor, Dysart, return the ninja to their former glory--or is he planning to exploit her for his own mysterious aims?"--.