Geronimo Stilton Secret Agent

This book is about Geronimo meeting a friend from school. His friend's name is Kornelious. Kornelious took him to his mansion. He told him a big secret which was that he was a spy. The next day Geronimo went to his office and he was given a letter. The letter had the deed that they owned that land that the office was on. He then had to go and look for envelope that held the deed. He searched in rubbish bins, the dump and the sewers. He fainted a couple of times but Kornellious and his sister saved him. When he finally found that letter his grandfather said that it was a copy and he said that he was trying to see how much the company meant to him. He proved that it was important to him.