Plot summary
Scorpion gets a mission directly from the U.S. President and works with the FBI on election day when hackers try to crash the voting servers in the latest U.S. presidential election. Since Walter is flagged by immigration as a person of interest for citizen fraud, he cannot help the team. Undeterred, he partners with Ralph to find out that the Chinese consulate and their ambassador are behind the vote hack as a means to gain control of international shipping lanes. Later, Paige goes with Tim to the Veterans' Ball and has to meet his parents.
Meanwhile, Agent Linehan visits the garage and, although she knows Walter and Happy perpetrated a fraudulent marriage, is forced to grant Walter his citizenship after Washington, D.C. enacts a private bill as a reward for his work on the case. Happy finds out she was not pregnant, her blood test a false positive caused by contracting cadmium poisoning after working on the solar panels, but she and Toby do get properly engaged.
Credits
Adapted from Wikipedia contributors, List of Scorpion episodes. HTML formatting and reference markers removed.