Clark Kent (Tom Welling) and Lois Lane (Erica Durance) become co-workers at the Daily Planet as Smallville begins its eighth season tomorrow night at 8 on Ch. 28 and 56.

THE CW / Marcel Williams

TV’s Smallville has weathered cast losses before. But this season, the eighth, faces a special challenge: Michael Rosenbaum, who played Clark Kent’s arch-enemy, Lex Luthor, and Kristin Kreuk, Clark’s first love, Lana Lang, have left the cast.

And, behind the scenes, the show’s creators, Miles Millar and Alfred Gough, are gone. The show is moving forward, though. And this season, which begins tomorrow at 8 p.m. on The CW (Ch. 28, 56), will feature major new villains, the return of some old allies and a new chapter in Clark’s life as he moves closer to his destiny as Superman.

With Millar and Gough gone, the series is now in the hands of Kelly Souders and her three fellow executive producers, who have all been with the show since Season 2.

Clark’s relationships with Lex and Lana have been key underpinnings of Smallville, Souders acknowledges, and so the departures of Rosenbaum and Kreuk are more than just bumps in the road.

“When we heard neither would be back full time, to say it was devastating is not overstating it,” she says. “However, we have these other great characters.” While Kreuk is no longer a regular, she will return for a handful of episodes, Souders assured. Similarly, while Laura Vandervoort, who played Clark’s Kryptonian cousin last season, is gone from the cast, she’ll make a return appearance.

As for Rosenbaum, “the door is always open,” Souders says. And Lex’s presence will still be felt, she says, even if he’s not there. Meanwhile, there are other relationships to explore, such as the one between Clark (Tom Welling) and Lois Lane (Erica Durance), who will become co-workers at The Daily Planet in Metropolis.

The two stars have an undeniable on-screen chemistry, Souders says — a good thing, since it’s Lois, not Lana, whom Clark is destined to be with. This season’s theme is double identities. As Clark spends more time in the big city instead of Smallville, he’ll find it tougher to swoop in to save the day and then escape unnoticed, Souders says.

“In Smallville, there were often only cows watching him.”

The double-identity theme also encompasses Clark’s best friend, Chloe Sullivan (Allison Mack). “Chloe has some sort of secret life going on that we will discover as well,” Souders says. And then there’s new cast member Sam Witwer, who plays paramedic Davis Bloome. Bloome’s alter ego is Doomsday, the creature who killed Superman in the comics — though Bloome, himself, is apparently unaware of his double identity. Over the course of the season, Souders says, Bloome will discover he’s not necessarily from this world and he’s not the good guy he thought he was.

“It’s kind of a tragic turn of events for him.” Adding to Clark’s headaches: Cassidy Freeman as Tess Mercer, acting chief executive of LuthorCorp in Lex’s absence. “You will sense very quickly that she has been mentored closely by Lex,” Souders says. “There’s a little bit of Lex in her.”

At least Clark will have some help against these new threats. The junior Justice League — Green Arrow, Black Canary and Aquaman — will show up in the season’s first episode to bail out Clark. And Justin Hartley as Green Arrow will be sticking around as a regular. “He’s just fascinating to play against Clark,” Souders says. Though the characters are allies, “there are parts of each other that they really don’t like about each other.”

While there have been reports that the eighth season will be the last, Souders says that hasn’t been decided and that there are plenty of stories left to tell. “We are doing our best, everyone’s working really hard, in hopes that this isn’t the last season.”