It's Halloween at Hearst College and while Veronica is at a party with Logan at Mercer's underground casino, the place is robbed by men in U.S. President masks. The thieves take Veronica's necklace, given to her by Lilly Kane. Veronica suspects that Weevil was behind the robbery and soon after the robbery, Sheriff Don Lamb arrests him. Lamb suspected Weevil because a pizza was delivered with a VISA card. Weevil insists to Veronica that he was framed and she takes the case. After a lengthy investigation, Veronica discovers that a couple of members of the campus police were actually behind the robbery and they framed Weevil because he was the newest Hearst maintenance employee. Veronica gets her necklace back.
Meanwhile, Dean O'Dell and his wife Mindy seek Keith's help in tracking down Steve Botando, the biological father of Mindy's son, who is deathly ill. Keith tracks Steve down, but Steve is unwilling to be the bone marrow donor. Soon after, Steve disappears and Keith becomes the leading suspect in his disappearance. Keith soon discovers that Steve was knocked out and taken to the hospital by Dean O'Dell so that they could take the bone marrow without Steve's consent. In the end, Steve is given Mindy's car in exchange for the bone marrow and Keith is cleared of all charges regarding Steve's disappearance.
Wallace, distracted by a new group of friends, struggles to pass his Mechanical Engineering class. One of his new friends directs him to a "tutor" who can give Wallace tests and answers in exchange for a fee. Wallace at first buys the tests and then succumbs to temptation and buys the answers. This does not work out well for Wallace, however, as he is caught cheating.
- The Asian man who was with Claire Nordhouse the night she was raped was her boyfriend. When Veronica shows Claire his picture, Claire claims she doesn't know him.
- "Busted" - Johnny Cash
Quotes and trivia
- The episode had an estimated audience of 2.70 million viewers on its initial airing. 
- The title President Evil is a reference to the zombie video game Resident Evil.
- This is the only Veronica Mars Halloween-themed episode.
- While working for a client, Keith uses the pseudonym "Adrian Monk". Enrico Colantoni was a guest star on an episode of Monk, playing a disgraced police officer who is a very astute detective, not unlike his character on Veronica Mars.
- For Halloween, Veronica and Logan are dressed as the members of the band The White Stripes, Veronica as Meg White and Logan as Jack White.
- Mercer Hayes, the host of the party, is dressed as Alex from the film adaptation of A Clockwork Orange. A possible foreshadowing.
- Robbers wearing masks of ex-Presidents was also used in the film Point Break.
- The robbers and Veronica quote the character Tony Montana from the film Scarface as played by Al Pacino.
- After arresting Weevil, Sheriff Lamb brodcasts "Hey good looking we'll be back to pick you up later" over the police car radio to Logan. This is a reference to a 1979 TV commercial for Mr. Microphone by Ronco.