Misterio en Buenos Aires by Fernando Andrés Ceravolo.
Four high-school students from Barcelona take a class trip to Buenos Aires to celebrate the end of the school year. In the Argentinian capital, the four friends come across a map drawn by a famous explorer and take on the role of detectives, embarking on a series of adventures in search of the mysterious treasure.
Mi Buenos Aires querido
Los barrios de Buenos Aires
Paperback, 80 pages and downloadable audio of the book.