Team Scorpion must put aside their personal and romantic predicaments when anonymous hackers with unknown motives take control of U.S. military aircraft and warships and point weapons at American cities, on the special two-hour third season premiere

Just as Team Scorpion makes headway against the hackers controlling U.S. naval destroyers, they learn that a U.S. nuclear submarine also has been hacked and has a missile about to launch, on a special two-hour third season premiere.

When Walter is accidentally launched into space in a rocket, he hallucinates about Paige as his oxygen runs low, and Team Scorpion works feverishly to find a way to bring him home before he suffocates.

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.

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.

Before Halloween, Team Scorpion must infiltrate a deep, vast cave system in order to prevent a bat population from destroying the North America ecosystem. Also, the team dons costumes to stage photos from Halloween's past for Walter's upcoming immigration inspection.

On Election Day, as democracy hangs in the balance, Team Scorpion is called on when someone tries to throw the U.S. presidential election into chaos.

When Team Scorpion travels to Ireland for Megan's one-year memorial, Walter discovers that a nearby lake's natural disaster has created a poisonous cloud that could kill everyone in the village. Also, Cabe and Toby try to alleviate the tension between Tim and Walter.

Paige's estranged mother calls on Team Scorpion when she accidentally uncovers a forgotten nuclear reactor on the verge of exploding.

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. Also, without Paige's knowledge, her mother, Veronica (guest star Lea Thompson), "helps" Ralph maximize his troop cookie sales.

It's Christmas Eve and Team Scorpion's electronics-free mountain getaway turns deadly when they come across gun-runners, and Ralph is kidnapped when they try to escape. Also, Tim makes an important decision about his position with Team Scorpion.

When a mission in the desert results in exploding shrapnel that seriously wounds Cabe, Team Scorpion must freeze his body in order to save his life.

When Team Scorpion is duped into producing counterfeit money for a foreign entity intent on ruining the U.S. economy, Paige must rely on her mother Veronica's (Lea Thompson) skills as a grifter to save them.

Team Scorpion must save a man teetering on the edge of a massive sink hole that threatens to destroy the Los Angeles water supply forever.

Team Scorpion's job to find sunken treasure goes awry when Walter and Paige's boat explodes, leaving them lost in the middle of the Pacific Ocean surrounded by sharks.

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.

When a simple mission to protect a vital seed bank goes awry, Team Scorpion must save Happy, Sylvester and Cabe, who begin suffering from life-threatening, fear-based hallucinations.

Following a severe storm, Happy's friend Ada (Mary Mouser), who lives in a sterile bubble to protect her compromised immune system, is left with dangerous debris on the verge of puncturing the structure. Now, Team Scorpion works to safely move Ada to a more secure location without risking her life.

To stop a dangerous virus from spreading, Team Scorpion must locate a rare endangered monkey in the Amazon that has the antibody for the cure. Also, Toby and Happy see a counselor (guest star Penn Jillette returns) to prepare for matrimony.

While on a mission to repair a turbine at a wind farm, Team Scorpion must race to save Paige and Happy before the cable holding the gondola they are in snaps and sends them plummeting to the ground.

Team Scorpion must defy the orders of a foreign government after they retrieve an asteroid from space containing DNA strands that could have deadly consequences once exposed.

Team Scorpion gets trapped inside a failing and dangerous biodome designed for Mars while trying to extract a pair of scientists inside.

Team Scorpion help Toby and Happy race to the altar to say "I Do" after a simple job extinguishing a tunnel fire becomes catastrophic.

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.

Three weeks after they crash land on a deserted island, tensions run high for Team Scorpion when they must battle to overcome their relationship obstacles in order to be rescued, on the third season finale.