- The Control Voice: Physical scars are evidence of a wound long since healed. But what about the wounds we can't see? What is left behind when there is trauma to the soul?
Scientists in the Arctic discover a species of Polar Mites that infest humans and cause them to become psychotic.
- The Control Voice: The suffering we conceal and the sorrow we hide may only be fully understood by those who share a common pain.
- Abusive Parents: William Grimes was abused by his father as a child.
- Beneficial Disease: The polar mites are unable to survive in Robby Archer's body as he suffers from polycythemia, which leads to an overabundance of red blood cells.
- Danger Thin Ice: Matt Archer was sucked under the ice and died while playing hockey with his brother Robby and their friend Jack Burrell.
- Hypochondria: Marcy Newhall, who works at the Peary University Research Station in the Arctic, has severe hypochrondria and checks her blood pressure everyday to ensure that it remains stable. When William Grimes and Lou Wolsky become infested with polar mites and go insane, Marcy is so afraid that the same thing will happen to her that she convinces herself that it already has. She stabs herself in the stomach and soon dies as a result. The autopsy later determines that she was never infested with the mites in the first place.
- Mind Virus: The people working at the Peary University Research Station in the Arctic are infested with polar mites which cause them to go insane, eventually leading to their deaths.
- Precision F-Strike: This episode is one of five to feature the word "fuck".
- We Used to Be Friends: Robby Archer and Jack Burrell were best friends as children but they drifted apart after the death of Robby's brother Matt. The three boys were playing hockey on the ice when it gave way and Robby and Matt fell through. Jack tried to rescue both of them but he was not strong enough. Matt insisted that he save Robby instead of him. Jack complied and Matt was sucked under the ice and died.