I don't have any information about the 'Moe School 5' novel collection. However, if it was referring to the Moe School series, then the episode where Maya lost her ability might be referring to the chapter of the Moe School Holy War. In this story, Maya, as one of the guardians of Moe School, once had the ability to control the elements, but she lost this ability in a battle and was expelled from Moe School.