On the 26th of July, 1864, a magnificent yacht was steaming along the North Channel at full speed, with a strong breeze blowing from the N. E. The Union Jack was flying at the mizzen-mast, and a blue standard bearing the initials E. G., embroidered in gold, and surmounted by a ducal coronet, floated from the topgallant head of the main-mast. The name of the yacht was the DUNCAN, and the owner was Lord Glenarvan, one of the sixteen Scotch peers who sit in the Upper House, and the most distinguished member of the Royal Thames Yacht Club, so famous throughout the United Kingdom.
Lord Edward Glenarvan was on board with his young wife, Lady Helena, and one of his cousins, Major McNabbs.
The DUNCAN was newly built, and had been making a trial trip a few miles outside the Firth of Clyde. She was returning to Glasgow, and the Isle of Arran already loomed in the distance, when the sailor on watch caught sight of an enormous fish sporting in the wake of the ship. Lord Edward, who was immediately apprised of the fact, came up on the poop a few minutes after with his cousin, and asked John Mangles, the captain, what sort of an animal he thought it was.
Captain Harry Grant, with his ship Britannia, has vanished, but a message in a bottle has been recovered. The message is heavily water-damaged, but Captain Grant's family and friends decide to do whatever they can to find him. It is an adventure that will take them, and the hapless geographer, Jacques Paganel, to South America, then to Australia, then to New Zealand, in a desperate attempt to decipher the message correctly and find Captain Grant before it is too late.
In English, The Children of Captain Grant is often title In Search of the Castaways, but is also often called Voyage Round the World. As is often the case with Verne, translations are a bit hit and miss, often being abridgements and modifications as well as translations. The best translation online is the three-volume George Routledge and Sons Voyage Round the World; Alexander Pruss has hunted down the three volumes and given the links here.