This story continues Thirteenth Child and follows it closely in time. Lan is away at a magical college back East and Eff is finishing Upper School and thinking about her future. She decides that she wants to continue working with Professor Jeffries and the menagerie at the Northern Plains College. Her real goal is to explore the land beyond the Great Barrier Spell. She also gets a chance to meet Professor Torgeson from Vinland and work with her. When an expedition is arranged to go out and collect samples from the lands beyond the Great Barrier, Eff is able to go along as Professor Torgeson's assistant. She becomes even more fascinated with the plants and animals in the unexplored West. Guiding the expedition is Wash Morris who is a circuit riding magician and a student of Aphrikan magic. Eff has known him since she was a student. She has been studying Aphrikan magic since she was in fourth grade. Her knowledge of Aphrikan magic was what helped her develop a way to stop the mirror bugs before they did even more damage to the settlements in Thirteenth Child. Eff isn't very good at Avrupan magic unless she is combining it with Aphrikan. In fact her spells have a tendency to fizzle out or explode!While they are on their expedition, they are asked to find out why a creek has stopped flowing near one of the settlements. They discover that an landslide has blocked the creek. Wash does a complicated bit of Aphrikan magic to get the creek flowing again and Professor Torgeson and Eff discover some strange rocks. They look like fossilized animals. When they bring some of them back to the college to study the find creates a frenzy. Everyone has a theory about what they are and everyone wants a sample.A new expedition to collect more of the strange rocks is being organized and Eff is ready to go when the family receives word that Lan has been in a terrible magical accident. Eff, along with her father and mother, travel for 2 and 1/2 days on the train to get to Lan. The rest of the family gathers too. The doctors and doctor magicians aren't able to help him. Eff quietly looks at him with her Aphrikan magic and unkinks his magic. Eff doesn't mention her role in Lan's recovery. Lan does recover but is feeling guilty that his teacher died and other students were injured. He is determined to give up the study of magic and come back home to Mill City.They arrive back in time to join the rock gathering expedition and discover that it is some sort of unknown magical creature that is turning animals into stone. Lan and Eff have to work together and use all their strengths when the newly named Medusa Lizard threatens the expedition and the settlements.This was another great episode in the Frontier Magic series. Eff is growing to know who she is and what she wants out of life and so is Lan. The world Wrede builds is a fascinating one with lots of wonderful new creatures. I only wish that William would have made an appearance in this story beyond being someone with whom Eff exchanges letters. Maybe we'll get a chance to catch up with what he is learning a Triskelion University in the final book of this trilogy - The Far West.