Extinction is the first episode of the fourth season of Scorpion, and the seventy-second of the series overall. It will air September 25th, 2017.
- Elyes Gabel as Walter O'Brien
- Katharine McPhee as Paige Dineen
- Robert Patrick as Cabe Gallo
- Eddie Kaye Thomas as Toby Curtis
- Jadyn Wong as Happy Quinn
- Ari Stidham as Sylvester Dodd