Jonathan Barnavelt is a fictional character from the book series "The Secrets of the Immortal Nicholas Flamel," written by Michael Scott. He is a young boy who discovers that he has magical abilities and is the key to a prophecy that could change the world. Throughout the series, Jonathan teams up with other characters, including Nicholas Flamel and Perenelle Flamel, to navigate a world filled with mythical creatures and powerful enemies. His journey involves learning about his powers and the responsibilities that come with them, as he faces challenges that test his courage and determination.