In Mission Oriental, Mr Ong was a personal secretary of the Sultan of Kulang. He went with Mr Preston of the Colonial Office to see Air Commodore Raymond with a request to evacuate by air the Sultan's heir, Prince Suba and the Sultana from the Sultanate of Kulang which had been surrounded by Communist terrorists. The lives of the royal family were also threatened by Prince Chan, an uncle of the Sultan who had designs on the throne. It was felt that once Prince Suba had been evacuated to Britain, the Sultan would be safe since killing him would not improve the uncle's claim on the throne.
When the extraction was approved, Mr Ong flew with Biggles and co. on a Handley Page Hastings transport to Kulang, Ong assisting with the navigation. When the Hastings had landed on the selected rendezvous, a beach near the palace, the Sultana and Prince Suba was not there. Ong offered to go into Kulang to find out what had happened. He returned shortly with news that Prince Chan started a revolution was in progress and there were riots in the town.
Biggles, unwilling to give up so easily, asked Ong to take him, Ginger and Bertie to the Sultan. Ong led them by an alternative route clear of the town, cutting through the jungle and the palace gardens into the palace. Ong took Biggles and co. into a council chamber where a standoff was in progress between the Sultan and his family on the one hand and Prince Chan with some Communist accomplices on the other. Biggles' firm intervention drove Prince Chan to the desperate step of drawing a dagger and attempting to kill the Sultan but Biggles moved quicker and shot the Prince instead.
With the crisis averted, Prince Suba and the Sultana left Kulang with Biggles and co. while Ong remained behind with the Sultan.