"Little Boy Lost" is the fourth episode of the third season of Scorpion, and the fiftieth of the series overall. It aired on October 24, 2016.
Team Scorpion must find a boy from Ralph’s class who goes missing on a field trip after he accidentally has a run-in with a deadly criminal. Also, Toby gets closer to finding out the identity of Happy’s husband.
Toby visits Mark Collins in prison, who gives him the riddle "The water lies still but still the water lies. Add 50 and your answer will be revealed".
- 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
- Happy is revealed to be pregnant with Toby's child.
- The identity of Happy's husband was revealed to be Walter O'Brien, whom she married so he keep his visa and eventually get citizenship.