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.

The Stitchers team is on the defense when Cameron and Detective Fisher are targeted in a shooting. Kirsten's stitch leads them to Robert Barbiero, a security expert who has worked with Maggie in the past and was close to Kirsten's mom. As Kirsten follows the clues that Ed Clark left her, she finds unexpected answers to long-held questions. Meanwhile, Linus is jealous when Cameron starts training Camille to be his back-up in the Stitchers lab.