In 2251, Kol-Tai was infected with the Saurian virus at the time the colony was visited by Dr. Leonard McCoy, who headed a massive inoculation program there. McCoy cured Kol-Tai of the Saurian virus. Unfortunately, soon after McCoy departed, the colony was hit by a massive plague. All of the colonists, except Kol-Tai, died from the plague, leaving the Dramian government to believe McCoy was responsible for the plague.
Nineteen years later, while the USS Enterprise was on an emergency mission to Dramia, McCoy would be arrested for a crime, which he was unaware of having committed. Attempting to get McCoy acquitted, the Enterprise traveled to Dramia II in search of a witness in favor of McCoy at his trial. There they discovered Kol-Tai, who regarded McCoy as a savior and a friend, and was willing to travel back to Dramia with the Enterprise.
On the journey back to Dramia, the Enterprise passed through an aurora. Moments later, Kol-Tai and the rest of the crew of the ship, except Spock, began to contract the plague. The Enterprise made it to Dramia just in time to break McCoy out of jail, and for him to find a cure. Once the plague cure was found, McCoy was able heal all aboard the ship, including Kol-Tai. It was at that time determined that the aurora was responsible for the plague, and with the added testimony from Kol-Tai, McCoy was acquitted of the crimes charged against him. (TAS: "Albatross")