Synopsis by Todd Thatcher
After thwarting last season's attempted nuclear attack on Los Angeles, Day 3 finds Counter Terrorist Unit agent Jack Bauer (Kiefer Sutherland) again fighting to protect the city, this time from a weaponized virus. But Jack is also battling a personal demon -- a heroin addiction he picked up while working undercover in a drug-smuggling ring run by terrorist Ramon Salazar (Joaquim de Almeida). At Jack's side throughout Day 3 is his daughter, Kim (Elisha Cuthbert), who took a desk job at CTU in the time between Seasons 2 and 3. Complicating matters is Kim's relationship with Jack's new partner, Chase Edmunds (James Badge Dale), whom she has been secretly dating. Further CTU romance is found between agents Tony Almeida (Carlos Bernard) and Michelle Dessler (Reiko Aylesworth), whose working relationship has blossomed into marriage. But it's a rocky union that's tested throughout Day 3, by everything from charges of terrorism to exposure to a deadly virus. Following the dissolution of his marriage to the first lady, President David Palmer (Dennis Haysbert) is deep into his reelection campaign. But privately he is still grappling with the lingering effects of the viral attack carried out by assassin Mandy (Mia Kirshner) during Day 2's final moments. New to the series is Chloe O'Brian (Mary Lynn Rajskub), a CTU senior analyst whose computer skills prove helpful during Jack's mission this season and beyond. Day 3 also features the first appearance of Wayne Palmer (DB Woodside), who serves as the new chief of staff for his older brother. While lacking in major guest stars, Day 3 does feature Zachary Quinto (Heroes) as rookie computer analyst Adam Kaufman, and Daniel Dae Kim (Lost), who returns for a second go-round as CTU agent Tom Baker.