What happened to Vovka Ryzhikov when he decided to make a scientific discovery and persuaded his classmate Lena to help him with this? What story did Vova get into when she went without an electric train ticket with her enterprising friend Petka? How was Petka a secret correspondent and what came of it? After reading the book, you will learn about other adventures of Vovka Ryzhikov and his friends, ordinary boys and girls, in whose life something extraordinary happens every day.