The cast of "Dallas" certainly gives great billboard, with new additions only enhancing its heat index. That said, the initial thrill of TNT's better-than-expected reboot -- followed by the sadness of Larry Hagman's death, which was deftly incorporated into the narrative -- has given way to a kind of shark-jumping malaise. Sad as it is to say, Hagman's flinty-eyed, mischievous smile gave the show its teeth, and the third season can't ratchet up the camp factor enough to compensate for his absence. Give the producers credit for surviving this long, but as "Dallas" currently stands, stick a Southfork in it; it's done.

What season two presented as "J.R.'s masterpiece" -- orchestrating his own death in order to achieve from-beyond-the-grave vengeance against a rival and protect his family -- would have been an appropriate place to call things quits. As is, "Dallas" returns with a good deal of unfinished business, despite J.R.'s sacrifice, as the family is left to keep battling for control of Ewing Oil under the tense combination of J.R.'s brother Bobby (Patrick Duffy) and son John Ross, aka J.R. III (Josh Henderson).

Wasting little time, the show seeks to establish some momentum by resetting the table in terms of shifting alliances and back-stabbling. That bit of shuffling places Elena (Jordana Brewster) in a new role, while enlisting an old friend (Juan Pablo Di Pace) to help her. Meanwhile, Elena's ex and Bobby's adopted son, Christopher (Jesse Metcalfe), rebounds pretty spectacularly by meeting Heather ("90210's" AnnaLynne McCord), who doesn't exactly look like she should be working as a ranch hand.

"Dallas" did such a nifty job of weaving its Calvin Klein-ad-friendly next-generation together with the original cast as to represent that rarest of reboots, one that paid tribute to the original without either bastardizing it or feeling awash in nostalgia.

Now, however, the show just appears to be recycling earlier beats, resulting in flourishes that feel more suited to daytime soaps than primetime serials. There's probably still a modest audience for that, but for a series where most of the machinations have to do with energy and power, "Dallas" simply appears to be running on fumes.

Nevertheless, TNT looks determined to get a bit more mileage out of the Ewings, using the drama as a lead-in to an utterly banal new reality soap, "Private Lives of Nashville Wives," which can't even make squabbling twin sisters interesting. The music-centric program also has the bad fortune to arrive at a moment where Nashville is already overexposed -- witness the eponymous ABC serial and A&E's "Crazy Hearts: Nashville" -- as networks continue to chase the Southern/rural audience with results as repetitive as a she-done-me-wrong song.

"You're not half the man your daddy was," Bobby snaps at John Ross during one exchange.

Nor is "Dallas" half the show it was without him.

2014 Variety Media, LLC, a subsidiary of Penske Business Media; Distributed by Tribune Content Agency, LLC