This book is a story designed to "spark interest in mathematics," written by the then-president of the German Mathematical Society in collaboration with a young mathematician, aimed at high school and university students, as well as the general public. The story begins when Lena, a high school student who is not good at math, receives a computer from her father. 【The Two People and One Thing? Appearing in This Book】 Lena: A high school girl living in Munich. She is not good at math, but she excels at swimming. She has a crush on her classmate, Jan. Jan: Lena's classmate. He cares for his younger brother and is kind to girls, and is a sportsman. Bim: A software program that can converse with humans. It's a bit of a jokester. Who developed it is a mystery. Knowledgeable and reliable, but a bit too meddlesome for just software?! This book takes the "shortest path" that appears in various everyday situations as its subject matter, and explains the mathematical theory behind it, namely the basics of graph theory, in an easy-to-understand way within the story, without complex mathematical formulas. It's an enjoyable read where you can naturally acquire the basic knowledge required for information science in university. Translated from the German edition.