Mark Benford (Joseph Fiennes) and Demetri Noh (John Cho) head to Hong Kong against orders on tonight's episode of "FlashForward" -- and ET is behind the scenes.

Against orders, Mark and Demetri jet to China to try to track down the mystery woman (Shohreh Aghdashloo as Nhadra Udaya) who previously phoned Demetri, telling him that she has information about the day he dies.

"We think we've got a lead on the woman who gave me the news that I was going to be shot, so we confront that woman," John tells ET. "It's a dazzler of a scene, I've got to say. It's some great stuff."

Joseph adds, "Demetri and Mark break protocol. They leave the States and fly over to Hong Kong to pursue this very strong lead, who seems to be very pivotal, pertinent to possibly knowing about the death of John's character. If we can crack her, we might be able to crack the future and prevent that from happening. We've come very close, but towards the end of this episode, there is some startling news. Just sort of mind wobbling, certainly to both characters as to how his demise will happen."

The one person who knows the secrets to Demetri's demise is Nhadra, but Shoreh isn't talking. She refuses to give us even a hint of what her character will be revealing to Demetri on tonight's episode.

"Not knowing what's going to happen tomorrow, in fact, is like real life," she says. "You and I don't know what's going to happen to us tomorrow, but we still do our chores today. As an actor, I wonder if it would make a difference to know or not to know, but I'm going to find out."

Also on tonight's episode, Lloyd (Jack Davenport) tries to come clean about his and Simon's (Dominic Monaghan) involvement in the global blackout -- against Simon's better judgment -- and Zoey (Gabrielle Union), who is engaged to Demitri, discovers the true meaning of her "FlashForward."

"FlashForward" airs Thursday nights at 8 p.m. on ABC.