Plot summary
After a hacker takes control over a neurotoxicity lab outside L.A., he uses the ventilation system to spread sarin gas throughout the facility that could kill 23 scientists trapped inside. And worse, he wants revenge for the Baghdad bombings in 1997, forcing Cabe to tell Walter his long-buried secret about the covered-up mission and the real end user for his code being the DoD and CIA who used it to kill and not help people. Ralph, wanting to prove he is a part of Scorpion, puts his life on the line to help them.
Also, Richard Elia stops by to give Walter a gift for his propulsion rocket, and loans him a Ferrari Testarossa to test its engine. Eventually, Walter kicks Cabe off the team and gets in a fight with Paige as she contemplates moving her and Ralph to Portland with Drew. Walter takes a late night joyride to clear his head in Elia's Ferrari but this goes awry when he has to take evasive action to avoid hitting a coyote.
Credits
Adapted from Wikipedia contributors, List of Scorpion episodes. HTML formatting and reference markers removed.