The team members set aside their personal and romantic issues when hackers take over targeted U.S. military aircraft and war ships, pointing the weaponry at American cities.
When Walter is accidentally launched into space in a rocket, Team Scorpion must find a way to bring him home before his oxygen runs out.
A boy from Ralph's class goes missing after having a run-in with a deadly criminal; Toby comes closer to discovering the identity of Happy's husband.
A simple job at the Los Angeles Natural History Museum turns deadly when thieves steal things from a rare gem exhibit to get the materials they need to make a nuclear bomb.
Team Scorpion explores a deep cave system in an effort to prevent a bat population from harming the North American ecosystem; the team dons Halloween costumes for Walter's impending immigration inspection.
On election day, someone tries to create turmoil in the U.S. presidential election, and Team Scorpion is called to investigate.
While in Ireland for Megan's one-year memorial, Walter discovers a natural disaster at a nearby lake has created a poisonous cloud that threatens an entire village; Cabe and Toby try to ease the tension between Tim and Walter.
When Paige's estranged mother stumbles upon a forgotten nuclear reactor precariously close to exploding, she calls on the team for help.
Walter takes a perilous swim to rescue a woman trapped in the La Brea tar pits; Paige's mother maximizes Ralph's troop cookie sales.
Team Scorpion encounters gunrunners while spending Christmas Eve at an electronics-free mountain getaway; Tim makes a decision about his place on the team.
Team Scorpion is forced to freeze Cabe's body after he's seriously wounded by exploding shrapnel while on a mission in the desert.
Team Scorpion must stop a catastrophe on Christmas Eve when heavy rain creates a large crack in a dam, putting an entire town in danger.
The members of Team Scorpion brave subzero temperatures in Antarctica to save a United States Special Forces unit; Toby risks his life to save Happy.
Sylvester's father, a retired general, asks the team for help when he thinks a dictator in Africa has uncovered weapons of mass destruction from World War II.
The members of Team Scorpion are asked to help NASA with a top-secret rocket launch, but they must sabotage their own mission when Walter's date finds a bomb strapped to her chest.
When a powerful earthquake hits Los Angeles, Team Scorpion must prevent a pinched gas line from causing a massive explosion.
Team Scorpion must stop an influx of drugs that are being smuggled into the country via drones; an ultimatum is issued.
Sylvester wins big on "The Price Is Right"; the team must infiltrate a high-end car smuggling operation that is preparing to ship weapons to South America.
The team investigates after the Los Angeles blood supply is hacked and tainted, which leaves a young girl who is in need of a heart transplant in peril.
The team must save Cabe when he is captured during a secret mission in Djibouti, Africa, with his protege, Tim Armstrong (Scott Porter).
A deadly tornado threatens the lives of Team Scorpion during a mission to recover the remains of fallen Marines in Vietnam.
The team is hired by the Department of Defense to test the security at Fort Knox by trying to break in and steal a precious artifact.
In Chernobyl, Sylvester and Paige become trapped inside a decaying nuclear reactor that the team is trying to repair before a tragic meltdown.
The team must outsmart mentally unstable ex-Scorpion member Mark Collins when he kidnaps Toby and threatens to kill him if his demands are not met.
Walter and the team ask a troubled former associate for help when a nuclear reactor in Los Angeles is on the verge of a cataclysmic meltdown.
After being accused of destroying a priceless piece of art, the team must pass a mandated psych evaluation; Paige asks the team for help when Ralph is hesitant to go to the school Halloween party.
Three convicts -- including a brilliant hacker -- escape from prison; Paige tries to manage Ralph's expectations when his dad returns.
A musician -- who created a controversial algorithm to generate hit songs -- helps the team investigate the murder of a music blogger; Drew seeks help connecting with his son.
The team must recover stealth technology from a military plane that was shot down in Bosnia; Walter's sister visits with Sylvester at the garage.
Sylvester ends up in critical condition after accidentally triggering an explosion during an investigation; the team must remain focused on finding the culprit.
On Christmas Eve, a boy is trapped in a beach-side cave, where the rising tide threatens his life; the team races to find a way to save him.