Larry Hagman's season two Dallas swansong as JR Ewing

When Larry Hagman died of cancer aged 81 in November 2012, his passing was mourned around the world. Just a few months after the star-studded UK launch for the revival of Dallas, the show had lost the man that made it a TV legend.

As the second season gets underway on Channel 5 (from 29 January), expect to see backstabbing, scheming, blackmailing, sibling rivalries, romantic betrayals, corruption and even murder.

More importantly, for the first six episodes, viewers will also have the opportunity to say a protracted fond farewell to Larry Hagman's JR Ewing - the iconic villain we all loved to hate.

Alongside JR will be younger brother Bobby (played by Patrick Duffy) and JR's ex-wife Sue Ellen (Linda Gray); the holy trinity from the original 1970s series.

For a while at least, JR's still very much a part of the second season. But his exit has been written into the script.

The new generation of Ewings will step up in season two: Josh Henderson is very good as John Ross, the ambitious son of JR and Sue Ellen Ewing, while Jesse Metcalfe is Christopher, Bobby's adopted son.

Jordana Brewster also stars as Elena Ramos, John Ross' girlfriend and Christopher's former fiancée, while Julie Gonzalo is Rebecca Sutter, Christopher's wife. In addition, Brenda Strong stars as Bobby's wife, Ann.

The second season will also feature Mitch Pileggi as Harrison Ryaland, Ann's scheming ex-husband.

As the new episodes begin, Sue Ellen's run for governor will be threatened by the secret that she bribed a medical examiner to help get John Ross off the hook for murder.

Ryland will come to Ann claiming to have news about her daughter. Christopher will head out of Dallas to find the real Becky Sutter, while the woman he married will start to show her true colours as Cliff Barnes' daughter.

JR will team up with John Ross to take over Sue Ellen's loan to Elena and, in turn, gain total control over Christopher and John Ross' new company, Ewing Energies. And that's in the first episode alone.

Larry Hagman's Dallas legacy

But - just as in the classic series - it's the amoral, unethical and unprincipled JR who is easily the stand-out character.

Larry Hagman's oil baron may have been older and frailer, but he still walked away with the first season thanks to his magnetic personality (and that glint of mischief in his eyes).

He could still deliver a one-liner as the likes of: "Blood may be thicker than water, but oil is thicker than both" and "Courts are for amateurs and the faint of heart" demonstrated.

When the new series kicked off in 2012, the rivalry between brothers JR and Bobby continued to be a key storyline, but it has also moved down to their sons.

Larry Hagman's death leaves an enormous hole; one that is, I fear, too large to fill.

If the show is to have a future, the acrimony between John Ross and Christopher must emulate that of JR and Bobby. Ideally, this should have been firmly established by the end of season one. But it wasn't.

While Josh Henderson is on his way to convincing as a chip off the old JR block, Jesse Metcalfe is a charisma-free zone, unfortunately miscast as the rather one-note Christopher.

If the central enmity is lacking, how can Dallas possibly move forward? It still relies too heavily on cast members from the original series to give it bite.

And don't get me started on Elena and Rebecca, the young love interests, as they've made about as much impact as a feather hitting the pavement.

For these reasons, I believe the revival is on borrowed time.

However, Larry Hagman's death is likely to inflate curiosity among casual viewers and so the opening six episodes must exploit that and lay a foundation for the future. If not, it will begin the slow ratings slide to cancellation.

As a huge fan of the original series, I hope this revival can survive and thrive. But it's difficult to imagine this reboot continuing successfully without its talisman; Larry Hagman was Dallas and Dallas was Larry Hagman.

• On Bing: watch fab clips of Larry Hagman in Dallas
• Larry Hagman's life in pictures: from I Dream of Jeannie to Dallas