In the most intense scene in “Changing of the Guard,” TNT’s first “Dallas” episode, Christopher angrily accuses Elena of exposing flaws in his methane hydrate project. She fires back by calling him out for dumping her – via e-mail! – on the day they were supposed to be married.

“I never sent you an e-mail!” Christopher exclaims. “I waited for you. For six hours! I thought you were dead, Elena. I was calling hospitals. I called Southfork. And when I finally got together with my father, he said you were in Mexico. And the next time I saw you, you had hooked up with John Ross!”

So begins one of the biggest mysteries of the new “Dallas’s” first season: Who sent the e-mail that broke up Christopher and Elena? The storyline produces more than a few twists, and as the Dallas Redone blog noted in June, it also evokes memories of another pair of star-crossed Southfork lovers who were kept apart by counterfeit correspondence.

During the classic “Dallas’s” seventh season, baby Christopher’s newly separated parents, Bobby and Pam, were on the verge of reconciling when they encountered interference from another relative: Pam’s conniving half-sister Katherine, who forged a letter in which Pam told her lawyer she no longer wanted to be married to Bobby but would return to Southfork to avoid hurting him.

Katherine, hoping to snare her sister’s husband for herself, showed Bobby the letter, knowing it would prompt him to give Pam the divorce he believe she wanted. The ploy worked and Bobby and Pam were kept apart.

In “Hush, Hush, Sweet Jessie,” the penultimate episode of “Dallas’s” seventh season, the truth finally came out. In a quiet, moving performance from Victoria Principal, Pam pours out her heart and tells her ex-husband she never wanted to end their marriage. The revelation confuses Bobby, who reminds Pam what she had written in the letter to her lawyer.

“What letter?” Pam asks.

The conversation is interrupted by a ringing telephone – symbolic, perhaps, of the bells going off in Pam’s mind. At the end of the episode, she confronts Katherine (played to wicked perfection by Morgan Brittany), who brazenly confesses to her forgery – prompting Pam to smack her so hard, Katherine falls onto a nearby bed.

Flash forward three decades: In “Truth and Consequences,” TNT’s fifth “Dallas” episode, after Christopher pulls Rebecca aside at the Ewing barbecue, she tells him Tommy sent the e-mail that broke up him and Elena – which leads to Christopher striking Tommy in front of the other guests.

Like Pam’s smackdown, Christopher’s punch offered a satisfying flash of catharsis for viewers who knew Tommy was secretly plotting against the Ewings. It also reminded us: The Ewing men may have a lot in common with their daddies, but sometimes they take after their mamas.

‘What Letter?’

What letter?

In “Hush, Hush, Sweet Jessie,” a seventh-season “Dallas” episode, Pam (Victoria Principal) stands at a window in her living room while Bobby (Patrick Duffy) rests on the arm of a sofa.

PAM: I laid awake most of the night, just thinking. Thinking about how sad everything is. There have been so many tragedies in the past couple of years. Mama’s dying. Now Mark’s dying. Our marriage breaking up. Sometimes I just can’t believe that we’re divorced. I don’t know, Bobby. We should have found some way to have made it work.

BOBBY: I don’t disagree with that.

PAM: I thought a lot about our splitting up. It wasn’t just your fault or the Ewings’ fault. A lot of it was my fault too. You don’t know this, but I came to Thanksgiving Square that day to tell you that I was ready to try again.

BOBBY: Try? Try what, getting back together?

PAM: Yes.

BOBBY: Well, that’s very strange. I was sure you didn’t want to.

PAM: Oh, Bobby, I wanted to. I always wanted to. I just didn’t know if I could. [Walks toward him, they sit together on the sofa] Anyway, before I could say anything, you told me that you were letting me go.

BOBBY: But that’s because of your letter.

PAM: What letter?

BOBBY: The letter that you wrote to your lawyer. Maybe it was a first draft or something. Maybe you didn’t even send it. But Katherine found it and read it to me. It wasn’t the easiest thing I ever listened to.

PAM: Do you remember what was in it?

BOBBY: You said you wanted out of the marriage. You didn’t want to divorce me. You were afraid it would hurt me. You were hoping that I’d let you go.

In the background, a telephone rings.

PAM: Katherine read you this letter?

BOBBY: Yes. And despite how I felt at the time, it made me realize you wanted a different life.

‘I Never Sent You an E-mail!’

What e-mail?

In “Changing of the Guard,” the first episode of TNT’s “Dallas,” Christopher (Jesse Metcalfe) angrily leads Elena (Jordana Brewster) into a room at Southfork and slams the door behind them.

CHRISTOPHER: You couldn’t wait to tell him.

ELENA: What?

CHRISTOPHER: About the methane. The earthquake. Everything I told you in confidence, you told John Ross!

ELENA: I don’t know what you’re talking about.

CHRISTOPHER: [Grips her arms] Don’t lie to me!

ELENA: [Pushes him away] Let go.

CHRISTOPHER: Don’t lie to me!

ELENA: I have no idea what you’re talking about.

CHRISTOPHER: John Ross tried to blackmail me. He said he was going to tell my father everything.

ELENA: I didn’t tell him anything.

CHRISTOPHER: And what you did? What you did was for nothing. Because he doesn’t love you. He uses people. And you want to know what’s really sick? I trusted you again.

ELENA: [Slaps him] John Ross doesn’t love anyone but himself? You look in the mirror, Christopher. You listen to your own words. I will always love you. [Crying] But we are two different people, from two different circumstances. I hope you understand. Was I really so wrong for you?

CHRISTOPHER: I have no idea what you’re talking about.

ELENA: The e-mail you sent me. The day we were supposed to get married.

CHRISTOPHER: I never sent you an e-mail! I waited for you. For six hours! I thought you were dead, Elena. [Crying] I was calling hospitals. I called Southfork. And when I finally got together with my father, he said you were in Mexico. And the next time I saw you, you had hooked up with John Ross! So what was I supposed to think?

ELENA: You sent me an e-mail saying that we were a mistake.

CHRISTOPHER: What?

ELENA: I only went to Mexico because I couldn’t stand to be here. John

Ross found me. I thought I wasn’t good enough.

CHRISTOPHER: No. [Touches her face] No. Don’t ever say that.

What do you think of Pam and Christopher’s moments of truth? Share your comments below and read more “Dallas Parallels.”