Hayden Panettiere and Jack Coleman, Heroes

If Heroes' previous season finales have taught viewers anything, it's that they can expect to see most of the superpowered good guys come together to bring down the villain.

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Robert Knepper, who plays this season's power-hungry, carnival-leading baddie, Samuel, promises more of the same in Monday's Season 4 send-off. But for Samuel, it's no more Mr. Nice Guy.

"Samuel never went up to Hiro [Masi Oka] and Peter [Milo Ventimiglia] and said, 'You're going to work for me.' He made them realize something about themselves that they needed to realize and hopefully they would thank Samuel," Knepper tells TVGuide.com. "There was this manipulative approach that didn't work out how he wanted it to work out. In the end, he's going to say ' ... I'm going to get you back. I'm going to show you my true colors — you're now working for me.' And if they don't, there's going to be a price to pay."

Claire Bennett (Hayden Panettiere) and her father (Jack Coleman) have already gotten a taste of what Samuel's willing to do: The most recent episode ended with them locked in a trailer and buried alive 50 feet underground. Coleman says it doesn't look good for Noah (aka HRG), but he and Claire will get to work out some of their problems.

"I think part of Samuel's evil plot is to have Claire watch HRG die, because his lungs will obviously collapse on him as the oxygen diminishes and hers will keep regenerating," Coleman says. "So, it's a pretty sticky wicket, but in the finale there are some pretty sweet scenes between the two of them that should be pretty touching. Even though there's been strain throughout the season, it never got to the point of 'I hate you and never want to see you again.' It was always mitigated by a sense of love, and the two of them have always been able to overcome their issues."

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So what brings the rest of the heroes to the party? Hiro still has a score to settle with Samuel for trapping his long lost love Charlie (Jayma Mays) somewhere in the time-space continuum. And Peter and Sylar (Zachary Quinto) are on a mission to prevent Emma (Deanne Bray), who's currently in Samuel's care, from killing thousands as Peter's vision has predicted.

"The people who had been aligned before all of a sudden might not be," Coleman says. "Hiro gets to have some sort of closure with the character of Charlie, and there's a very interesting bookend to the first episode of this volume involving Tracy [Ali Larter] and water."

As for Peter and Sylar, Matt Parkman (Greg Grunberg) stands in the way of them saving the day. Even though Peter freed Sylar from being trapped in his own nightmare, Grunberg says Parkman is still the gatekeeper.

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"Parkman is really in control of who is going to be able to affect the ultimate outcome," Grunberg says. "[In their minds], they've experienced three years, and Sylar has redeemed himself in the eyes of Peter. But for Parkman, it's been 30 minutes and he says, 'You're not going anywhere.'

"Parkman's gone a little loopy and a little dark," Grunberg continues. "Over four years of the show, there's all this mistrust. So, Parkman has finally taken this into my own hands. It's very clear that he can control anybody he wants. He's really the guy who's holding the cards and he's more powerful than anybody ever anticipated."

Watch previews for the Heroes finale in our Online Video Guide

As for hard details about how the drama unfolds, the cast is characteristically mum. Coleman only says that Claire plays a pivotal role. "Obviously, there is a showdown with Samuel," Coleman says. "But at the very end is Claire sort of blowing the lid off everything. ... If you go back to the pilot and how we first met [Claire] — jumping off the oil rig and resetting her shoulder and talking into the camera — there's a bit of harkening back to that but with much larger implications. So, that would kick off the next volume."

But will there be a next volume? Ratings for the oft-criticized show have slid to all-time lows for the series. However, NBC's schedule is wide open in light of the network's recent late-night woes. Coleman says the volume's end has a certain finality to it, but he would like the chance to more adequately wrap up the characters' arcs.

Grunberg is more emphatic. "I cannot imagine this as our series finale," he says. "People will be incredibly disappointed. They will be pleased with the end of the volume, but as a series finale, it's not even close. That's what gives me hope."

What do you want to see in the Heroes finale? Are you hoping for another season?