Team Scorpion try to protect Cabe's ex-wife, after she uncovers evidence that suggests foul play in the death of a prominent congressman.

Team Scorpion goes undercover on a cruise ship to locate and disable deadly stolen rockets. Meanwhile, as Valentine's Day approaches, Toby and Happy help Ralph, who is in the throes of his first crush.

Team Scorpion helps the CIA locate a top-secret aircraft in Area 51 in order to raise money for Walter's research to save his sister's life.

Team Scorpion is tasked with helping NASA’s top secret rocket launch, but they must sabotage their own mission when Walter’s date from the previous night has a bomb strapped to her chest.

Walter must swim through the deadly La Brea Tar Pits when Team Scorpion helps a woman trapped in the tar before she runs out of oxygen.

Walter and Sylvester enter an international chess competition under cover on foreign soil for Team Scorpion in order to extricate a U.S. spy before her identity is exposed.

On Thanksgiving, Team Scorpion's new neighbor, Florence, joins them at sea on a mission to destroy a floating island of trash, but her flawed contribution leaves her, Walter and Happy stranded on the quickly dissolving island. Also, Toby works with Cabe to uncover the details of his father's death that he has suppressed since he was a boy.

Team Scorpion heads to the bayou to track down a cagey alligator in order to stop a deadly mosquito-borne virus, and Paige teaches Walter the concept of the “white lie.” Also, Walter hits Cabe with a tranquilizer gun and Toby must save his life, and Sylvester and Ralph help Patty when the mean girls at her school force her to get a dreaded tardy slip.

Team Scorpion must use their high IQs to win a softball game when the homeland director challenges, with all of their future government contracts on the line. Also, Walter’s secret night out with Florence puts Toby and Happy on edge.