While visiting Onderon on business, the Tweigar landed in Iziz and Gormo's starport visa was stolen while he was in the city. Stranded without a starport visa in Iziz, Gormo was unable to travel back offworld or even return to his ship at the starport. Unsympathetic Onderonian soldiers refused to allow Gormo through the starport entry checkpoint, even after the Tweigar's crew came out and vouched for him, confirming he was their captain. The stubborn adherence of the Onderonian soldiers to protocol- that no one could enter the starport without a starport visa- infuriated Gormo, and in conversation with Meetra Surik, he vowed that if he succeeded in leaving Onderon, he would never be coming back.
The ultimate fate of the Tweigar partially depends on the actions of Meetra Surik. Gormo is one of the individuals to whom Surik can give one of the two open starport visas she comes into possession of. If Surik does give one to Gormo, he immediately returns to the starport, rejoins his crew aboard the Tweigar, and departs Onderon. If Surik does not give a starport visa to Gormo, the crew of the Tweigar was either stuck on the planet still waiting for Gormo when the Onderon Civil War started, or was forced to take off and leave without him.
Gormo actually mentions the possibility of his crew having to leave without him, noting that between the likelihood of a civil war on Onderon at the time, and the fact that his ship is operating on a busy shipping schedule, his crew cannot wait for him indefinitely.
The Tweigar is never actually seen in-game, only referred to by its captain in conversation with Meetra Surik.
- Star Wars: Knights of the Old Republic II: The Sith Lords (First mentioned)