In terms of scientific validity, the latest episode of Fringe--'What Lies Below'--may be a stretch, but it does still retain the tension and mystery that is typical of a Fringe episode.
The Virus Before Time
Although the symptoms of the virus is reminiscent of rabies and similar viral diseases, Walter's sudden extrapolation of a possible explanation for its dormant state seems like a stretch to me. Indeed, it is not all the scientific flair around him that gives him the ultimate solution,...