To fix a Los Angeles nuclear reactor that's on the verge of a cataclysmic meltdown, Walter and the team must reluctantly enlist the help of a troubled former member.

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 must help Ralph when the FBI questions him after his dark web game play inadvertently reveals the location of a CIA safe house and results in the murder of CIA operatives.

While on a mission to save lost hikers, Team Scorpion’s helicopter crashes, igniting a massive wildfire that quickly closes in on them. Also, Sylvester must help their injured pilot who is unable to make it to safer ground.

Sylvester goes undercover in a federal prison in order to save the lives of three judges, but the team must help him escape when his life is threatened.

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.

Team Scorpion’s mission to recover the remains of fallen Marines in Vietnam is threatened along with their lives when a deadly tornado heads directly towards them.

Team Scorpion’s simple job at the Los Angeles Natural History Museum turns deadly when they discover thieves robbing a rare gem exhibit in order to get materials needed to enrich a nuclear bomb.

While en route to Toby and Happy’s honeymoon, Team Scorpion’s plane crash lands on a remote deserted island, leaving them all with little hope for rescue.

While decommissioning an old nuclear missile, a simple accident causes Team Scorpion to endure exposure to toxic vapor while trying to prevent the nuke from detonating. Also, Paige confronts Happy about constantly tagging along with her and Walter.

On Christmas Eve, when Walter chooses work over spending quality time with his friends, he falls down the stairs and hits his head, and as he lays unconscious, he enters a dream world where Team Scorpion never existed.

Team Scorpion inadvertently crashes a bank robbery in progress and is taken hostage. Also, Sylvester’s feelings for Florence grow.

Team Scorpion heads to Northeast Africa where they must carefully navigate a minefield in order to save the lives of local villagers. Also, Paige and Walter’s relationship takes a shocking turn, and Toby and Happy make an important decision.