In 2290, the T'Ong was dispatched on a "crucial" long-range mission from the Klingon Empire under the command of Captain K'Temoc. Due to the long travel time involved, the T'Ong's crew was placed into cryogenic sleep for the journey. The crew awakened, unaware that the Empire and the Federation were no longer at war. The cruiser returned and was heard from in 2365, when the ship sent out an automated signal directed to the Klingon High Command.
The T'Ong's signal was also picked up by Starbase 336, notifying the Federation of its location as well. Realizing the danger to lightly-defended Federation colonies in the sector, including those in the Boradis system, the USS Enterprise-D was dispatched to intercept the T'Ong, with Federation special emissary K'Ehleyr as an adviser. It was initially believed that the destruction of the T'Ong was unavoidable once the revived Klingons were confronted by their former adversary.
The Enterprise confronted the T'Ong when Lt. Commander Data picked it up on sensors but the T'Ong fired its phasers at the Enterprise causing no damage to its shields. The T'Ong then cloaked and went to warp. The Enterprise over took the Klingon ship at warp 8, during which the T'Ong dropped out of warp and decloaked. The T'Ong fired its phasers again causing no damage to the Enterprise's shields.
The T'Ong's crew eventually stood down when Lieutenant Worf masqueraded as the captain of the Enterprise and convinced Captain K'Temoc that the Federation and the Klingon Empire were now at peace. K'Ehleyr took command of the vessel and assimilated the crew to the 24th century while waiting for the IKS P'Rang to escort the ship back to Qo'noS. (TNG: "The Emissary")
- See: IKS T'Ong personnel
|IKS Amar • IKS B'Moth • K'Nera's battle cruiser • Kang's battle cruiser • Kronos One • IKS T'Ong • Unnamed|
According to the script for the episode, the pronunciation for T'Ong was "TOONG". 
The Starships RPG sourcebook gives its registry as IKC-7713.