M'Ola and her family traveled to Babylon 5 seeking a cure for Shon's condition when doctors on their own homeworld told them there was no hope of saving him. Dr. Franklin explains that he can save Shon, but it will involve a surgical operation, which is forbidden according to their beliefs. M'Ola explains that surgery on their people releases the soul.
Dr. Franklin tries to persuade them. When he is unsuccessful, he asks Cmdr. Jeffrey Sinclair for permission to operate despite the parent's wishes. Tharg and M'Ola plea to the commander, and when he does not decide right away, they believe he will side with Franklin over them. They appeal to every major ambassador on the station, but are turned down by each. Sinclair finds in their favor anyway, but Franklin commences with the operation nonetheless.
Believing their son lost his soul in the operation and is no more than an empty shell, they took their child's life in a ritual.
Tharg and his family made their sole appearance in Believers.