The Cheese Experiment (Geronimo Stilton #63)

When you're with Geronimo Stilton, it's always a fabumouse adventure!

New Mouse City was in a panic. A strange epidemic had broken out -- mice everywhere were covered in weird blue spots! Mouse Island's most famouse doctor immediately set to work with his team to try to find the cure... but someone was trying to stop him. Could I figure out who before I ended up blue myself?