x = 0 (Background info)

Lex thinks she is leading a normal life in the world of Arte Matematica until she gets randomly promoted by the emperors and one of her friends disappears from school without a trace. Shocked, she searches for answers, only to discover that the king and queen are the ones who have been kidnapping students. With the help of her friends, she goes on a quest to save the missing students and defeat the tyrannical rulers.