Jeremiah Stilton #62: The mouse in the sea!

Paper cover English language I was invited me and my family, Jeronimo Stilton, to Lisbon, Portugal, to follow the journey of the great explorer Vasco da Gama. He was the first European to reach India by sea — and apparently one of the ancestors of the Stilton family! But as soon as we boarded the boat, I knew that someone was trying to sabotage the trip. Can I find out who?