Past and Present

Plot:

On the planet Vyus, SG-1 discover an entire early industrial society suffering from collective amnesia since an unspecified event about a year ago known as the Vorlix. The most lucid local, scientist Ke'ra, develops an almost amorous relationship with Daniel while she shows the team the fascinating diary of a deceased scientist, which also mention a pesticide Dargol which had to be banned because it affected fertility and a 'visitor' named- Linea, who fits the description of the Destroyer of world SG-1 inadvertently helped escape (in "Prisoners") with them from a penal planet. Ke'ra and a Vyus couple, Orner and Layale, come to star-base where Dr. Frazer proves Ke'ra has Linea's DNA, and the amnesia is caused by a physical block in the brains caused by Dargol, which Linea developed into an experimental fountain of youth, which apparently suddenly went wrong. Manufacturing a medicine within a reasonable time, before ignorance ruins the planet, is hopeless without Ke'ra/Linea, but shouldn't she rather be incarcerated then given the chance to play another diabolical trick if she remembers her evil persona?