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

When Sylvester accidentally triggers an explosive device during an investigation, Team Scorpion must focus on finding who's responsible even while their friend's life hangs in the balance.

Team Scorpion is tasked with uncovering a mole inside the CIA who is being coerced into stealing deadly chemicals. Paige gives Walter a flirting lesson in preparation for the case.

When a conflict in Eastern Europe threatens to escalate, Team Scorpion is called on to help facilitate secret peace talks to prevent World War III.

To protect a key witness who is en route to testifying against a deadly drug cartel, Team Scorpion takes her on the run, with the cartel hot on their heels.

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.

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.

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.

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.