A puzzling car accident leaves a brain researcher dead, and Kirsten's determined to uncover what happened. Meanwhile, Kirsten wants Linus' assistance in decoding a clue left by Ed Clark; and Kirsten seeks info on the roots of the Stitchers program.

It's Kirsten's birthday and the Stitchers team is assigned to look into a disease researcher's suicide. When the body begins showing signs that it is carrying a deadly virus, the whole lab is placed under quarantine. The team jumps to action as they search for a way out, racing against the clock as, one-by-one, they come down with symptoms of exposure.