The little cat's story begins while sitting outside at the harbor on Hong Kong's Stonecutters Island, near fishermen who sometimes give it a little fish, in a harbor filled with giant ships. It's also telling of other cats (eg. JoJo, Uboat, Chairman) in the area, exchanging stories with each other - except for Chairman. Chairman is very territorial and gets angry at trespassers. The others are international travelers. And then something grabs his tail - it's a human (George) with warm hands, and he's soon carrying the little cat onto a ship, or rather sneaking the little cat on board. And soon afterwards, the little cat has a name - 'Simon.'
George soon is asleep, snoring along with other humans nearby, and a bit later a furry dog (Peggy) appears - she's a regular on the ship and not like the mean dogs on shore that bark and chase cats. Simon then follows Peggy for a tour of the HMS Amethyst, a destroyer that had made it through WWII.
Peggy's friendship with Simon quickly convinces the Captain that Simon should be treated well, and the danger of being thrown overboard as an unwanted stowaway passes. He's then assigned the duty of 'rat catcher' and given the rank of Ordinary Seaman. And then everyone prepares for patrol duty to protect British interests around the Straits of Malaysia.
Simon quickly ingratiates himself with the crew, particularly through his skill at catching and killing rats. There was no doubt what was happening - Simon would often leave presents of dead rats in sailors' beds and sleep in the captain's cap.
Official orders than mandated that the Amethyst travel up the Yangtze River to Nanjing. Once there, Communist guns opened fire, with one round landing in the captain's cabin - killing the captain and seriously wounding Simon. Simon's burns and four pieces of shrapnel made his recovery unlikely, but with help from the surviving medical staff he did survive. Meanwhile, the ship had again become overrun with rats while anchored in the river. Simon was soon back to work.
Simon also became a celebrity, lauded in world news, presented with the 'Animal Victoria Cross,' the 'Dickin Medal,' and promoted to 'Able Seacat.' Thousands of letters were sent to him, and he was presented with additional honors at every port.