Mickey thinks the doctor is working secretly as a teacher at a shady school. While the doctor observes that the chips appear to increase the pupils’ intelligence, Rose, who works as a dinner lady, observes that the cafeteria’s chips negatively impact other kitchen employees. The media has taken notice of Mr. Finch’s achievement; the Doctor’s old friend, investigative journalist Sarah Jane Smith, shows up at the school and finds the TARDIS. She joins the Doctor, Rose, and Mickey, accompanied by her robotic dog, K9. In order to give the Krillitanes complete control over time and space, they learn that the teachers are actually Krillitanes and that the chips are sprayed with Krillitane oil, which is meant to make the kids smart enough to decipher the “Skasis Paradigm,” a theory of everything. The doctor evacuates the kids and declines to join the Krillitanes. K9 destroys the school, the Krillitanes, and himself as he blows up the chip oil bottle. The Doctor offers to accompany Sarah Jane on the trip, but she suggests Mickey take his place. The Doctor gives her a brand-new K9 model before she leaves.