Abrams' new "Lost" is a new ratings blockbuster. When "Alias" starts its fourth season tonight, behind "Lost," big things are possible.

"I never know what to expect," Abrams, 38, insists. Still, he grants that this may be the year that "Alias" gets a big audience — thanks to "Lost." "We've never had a compatible lead-in. This is the first time that we've followed a series that has mystery and intrigue."

Mystery and intrigue are things "Alias" has in excess. On the surface, it is a show about Sydney Bristow (Jennifer Garner), a beautiful superspy. Beyond that, are endless tangles within the CIA and within her family.

Critics raved, but casual viewers had trouble jumping in, especially during reruns.

Jennifer Garner stars in "Alias." After three mediocre seasons, the show has refocused and found an appealing time slot. Associated Press library photo

Abrams says the two-hour "Alias" opener will be easy for newcomers to follow.

"We're not going to have any reprise (of previous seasons)," Abrams says. "We're not going to have any explanation. ... In no way is this first episode imposing or convoluted."

Especially early in the season, "There are a number of episodes that very much have a beginning, middle and end," Abrams says.

As the season goes on, he says, "Alias" will move back into larger schemes. "Hopefully, people will be so invested in the characters that they'll enjoy the ride."

As the third season was ending, Abrams says, he realized the show needed a makeover.

"Alias" had taken a daring route: Sydney woke up in Hong Kong. There was a two-year gap in her life and everything had changed. It was a clever idea, but Abrams said the result had flaws.

• Michael Vaughn (Michael Vartan) was married. "That precluded any relationship with her."
• Arvin Sloane (Ron Rifkin), Sidney's scheming ex-boss, had been moved to the sideline.
• Marvin Dixon (Carl Lumbley), once her understanding partner, had been promoted and distant.
• Sydney had no personal life. "We need to see her at home," Abrams says. "Sydney at rest was just her in a suit at the office."

Some changes started late last year. It turns out that Sydney has a half-sister, now a key part of her life. Growing up, Sydney didn't know that her father, is a spy. She didn't know that her dead mother was actually alive and running an evil agency. Now Sydney has half-sister.