When Simon, a mischievous young cat, is smuggled on board HMS Amethyst, his simple life amidst the streets of Hong Kong is transformed into an adventure fit for heroes.
But alongside new friend Peggy, the ships dog, he discovers a mortal enemy in king rat Mao Tse Tung.
Under heavy fire from the Chinese Communists, the ship runs aground, stranded for 101 agonising days. Despite severe injuries, Simon and the crew bravely battle their respective foes, enabling Amethyst to make an epic escape. Heralded worldwide as heroes, they sail into Plymouth to a jubilant welcome, but further heart-rending tragedy.