A Claim to Magic

Corrie and her twin sister, Betsy were going to Muta, a school at which they would learn magic, make friends, and save everyone on an adventure that would forever change them.
Corrie is the smartest in her grade, she's most likely the definition of "nerd", and has hardly any friends, she is not athletic and has hardly any belief in herself. What'll happen when she tries to save the world?