SG-1 discover 9 Goa'uld all dead for many months. However they were locked from the inside and there was no way the anything got out, and so what killed them was unknown. SG-1 go back to Earth to send a medical team to investigate, taking with them a stone tablet which might have the answers if Daniel can figure out how to work it. When they get back to the SGC Daniel starts hearing voices no one else can and acting very strangely. Soon after he has to be locked up, and Kinsey blames the Stargate for Daniel going mad and tries to shut it down once more, however, when the SG team visits Daniel he realises whats happening to him when he sees something come out of him go into him. When he tries to tell the others they believe its another delusion. However, after a while Teal'c starts to become sick, his Goa'uld seems to be dying. With the creature out of his body Daniel starts to become more focused and realises that it was infact not a creature but a machine of a sort created by Michello to defeat the Goa'uld with the side effects of it going into a human being a Schizophrenia. When the doctors come to give him medication, he tries to tell them, and asks them to find out the condition of Teal'c. With Daniel back, and out of the Mental Asylum, he is able to try and figure out where it came from. When he looks over the catalogue of the devices found in Machello's home they find a device similar to one they found locked with the 9 Goa'uld. Upon examination they realise that each device holds 10 of these machines, meaning one remained after killing the Goa'uld which went into Daniel but is now in Teal'c. However before they can do anything else, they go inside Jack, Janet and Sam. However, Sam seems unaffected by it, and discovers it is because of the unique protein markers left in her body by Jolinar when she died. She gives those protein markers to Jack & Janet who are instantly cured. They then give it to Teal'c and he is saved.
 Mistakes During Filming
- Before the credits, the camera zooms in on one of the dead Goa'uld. If you look closely, before the credits start, you can see one of the corpses eyes are actually open
- At one point when Daniel is just entering or exiting his room, you can see the velcro circle where the SG-1 patch should be and as established by military protocol and previous episodes, staff on duty always wear their patche
 Mistakes in the Script
- When Sam centrifuges her blood sample she only puts one tube into the centrifuge. Centrifuges must be balanced with an equal-weight sample on the opposite side when spinning.
|O'Neill: Then why don't we just put a little sign at the base of the ramp that says: "Gate travel may be hazardous for your health"?