The Vyans, native to Vyus, had been visited by Linea, the Destroyer of Worlds. Working with Dr. Zirvis, she had experimented with dargol, a chemical pesticide which had the ability to slow the aging process. Her experiments to restore youth led to an accident in which enhanced dargol gas entered the population. The chain reaction caused the entire population to become instantly young, their elders and children apparently missing, and with no memories from before the accident. This event, known as the Vorlix, had disastrous effects on the planet's development, and a year later, industry and agriculture had come to a virtual halt. With the help of the SGC, an antidote was found to reverse the effects of the amnesia. Although the population remained young, the memories of their past were restored.
Cross Reference: Dargol, Ke'ra, Linea, Mayris, Orner, Vorlix, Vyus
Episode Reference: Past and Present