When a military plane is shot down in Bosnia, Team Scorpion must help recover its stealth technology before it falls into enemy hands. Meanwhile, Walter's sister takes a break from her MS treatment and spends time at the garage with Sylvester

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.

Walter finally learns Cabe’s long-kept secret regarding the Baghdad mission, and it threatens to tear Team Scorpion apart forever. Also, Paige’s world is rocked when Ralph puts his life in danger to help the team.

The new Director of Homeland Security, Adriana Molina, reunites the team when a nuclear powered Russian satellite is knocked out of orbit and must be diverted before it detonates over Southern California. Paige and Walter face their feelings for each other when hospital footage reveals that Paige kissed him.

Walter’s attempt to “normalize” goes horribly wrong when a nefarious virus is uploaded to his computer, turning Team Scorpion’s new “smart” building project into a burning death trap with people locked inside.

When Team Scorpion and Walter's parents visit Megan in the hospital as her health deteriorates, they are quarantined after a deadly fungus outbreak threatens to infect everyone.

While Team Scorpion works to stop an influx of drugs being smuggled into the country via drones, Walter gives Happy and Toby an ultimatum on their new relationship.

Team Scorpion must outthink their unstable ex-Scorpion member, Mark Collins, after he kidnaps Toby and threatens to kill him unless his cunning demands are met.

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.

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.

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.

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.

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 with each other in order to be rescued.

Team Scorpion must work with their old nemesis Mark Collins in order to prevent the extinction of mankind. Also, Walter and Paige awkwardly navigate their new relationship.

Team Scorpion continues to work with their nemesis, Mark Collins, in order to prevent an extinction event that could end humanity. Also, Cabe’s last-minute decision while on the case leads to the possible end of his career.

While tracking a device that can prevent a nuclear meltdown through the Los Angeles sewers, Walter learns the nuances of listening and not offering advice to Paige. Also, Team Scorpion meets Florence, their new neighbor at the garage, after she sends a mix of smelly chemicals through their shared ventilation as a warning to keep the noise down.

As Cabe’s trial looms over Team Scorpion, a simple case goes sideways when they help a father and his daughter whose plane crashes nearby. Also, Paige helps Walter navigate his feelings about Cabe’s possible future in prison.

A solar storm knocks out power in Los Angeles, and Team Scorpion must help a teen pilot and his girlfriend who are lost over the Pacific without navigation or radio contact. Also, during the crisis, Walter must look after a group of Ralph’s classmates, and Cabe tries to tell Allie finally that he loves her.

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.