| Episode cast overview, first billed only: | |||
| Tom Welling | ... | Clark Kent | |
| Kristin Kreuk | ... | Lana Lang | |
| Michael Rosenbaum | ... | Lex Luthor | |
| Eric Johnson | ... | Whitney Fordman | |
| Sam Jones III | ... | Pete Ross | |
| Allison Mack | ... | Chloe Sullivan | |
| Annette O'Toole | ... | Martha Kent | |
| John Schneider | ... | Jonathan Kent | |
| John Glover | ... | Lionel Luthor | |
| Robert Wisden | ... | Gabe Sullivan | |
| Tony Todd | ... | Earl Jenkins | |
| Michael Eklund | ... | Will | |
| Andrew Johnston | ... | SWAT Commander | |
| Michelle Goh | ... | Suki | |
| Mitchell Kosterman | ... | Sheriff Ethan Miller | |
Former Luthor Corp employee Earl Jenkins, and who also worked at the Kent farm, has an unknown disease that violently shakes all his body. He arrives at the Kent farm during a party Clark throws while his parents are out of town and claims that the disease developed following an explosion at his former workplace: Level 3 of Luthor's Smallville plant which was experimenting with meteor-rock laced fertilizer. Trouble is, there is no Level 3! Determined to prove his case, Earl breaks into the plant and takes a class touring the plant hostage. Lex arrives with the police and trades himself for the hostages, while Clark stays behind to try to help Lex and find out more about 'Level 3' which Lex claims to know nothing about. But Lionel apparently knows about the mysterious secret underground level when he arrives with his personal goon army determined to keep the secret experiment under wraps... at the expense of anyone, even his own son Lex. Written by Claudio Carvalho, Rio de Janeiro, Brazil
The former employee of the Luthor Corporation, Earl Jenkins (Tonny Todd), has an unknown disease that violently shakes all his body, and claims that it was contracted in an inexistent Level 3 of the plant. He accidentally kills a man, and kidnaps Clark Kent's high school class during a visit to the plant, trying to contact Lionel Luthor (John Glover) and prove his assertion.
In my opinion, "Jitters" is the best episode of "Smallville" up to now. The last scene of this dramatic episode is very touching, when Lex Luthor, my favorite character of this series, observes close to his own father the reaction of the Kent family when Clark Kent returns safe and sound to their arms. My vote is ten.
Title (Brazil): "No Limite" ("In the Limit")