After Team Scorpion fails a military training mission, they are determined to prove their worth to Cabe and Homeland Security when a bomber threatens to take out the internet infrastructure of the entire Southwest.
Scorpion asks a music artist for help after he creates an algorithm that can produce popular songs and may find the killer of a music blogger; Drew asks Walter to help find a way to make a connection with his son.
Team Scorpion is tasked with uncovering a mole inside the CIA whose judgment is clouded by matters of the heart and is being coerced into stealing deadly chemicals. Also, in preparation for the case, Paige gives Walter a flirting lesson.
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.
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.