[12] Vernon reprised the role in the television film Battlestar Galactica: The Plan,[9] which was released digitally on October 27, 2009,[13] and first broadcast on SyFy on January 10, 2010.

[14] Ellen is introduced as the beautiful but troublesome wife of the gruff Colonel Saul Tigh, XO of the Battlestar Galactica and second-in-command to its captain, Commander William Adama (Edward James Olmos).

[6][17] Ellen has been described as the Lady Macbeth of the series in that she believes her husband should command more respect and power, and she has spent years manipulating him and other men to get it.

Moore noted that though Tigh is an effective leader during a military crisis, he is otherwise hampered by his lack of political skill, his alcoholism and Ellen's manipulation.

[7] Describing the situation surrounding Ellen's death as "Tigh's best moment of character development", Craig Elvy of Screen Rant lamented that it was rendered meaningless by her resurrection in season four.

[20] In the series, a race of sentient machines called Cylons launch a cataclysmic attack on human civilization that kills billions, and subsequently pursue the fleeing 50,000 survivors to exterminate them completely.

"[10] In "No Exit", Ellen makes the case to fellow Cylons Cavil and Sharon Valerii (Grace Park) that the value of humans is their ability to love, adapt, feel emotion, show compassion and be creative.

"[27] Several reviewers praised the elevated version of Ellen introduced in "No Exit", who is depicted as shrewd and commanding, yet compassionate, while noting that some of her core character flaws emerge in the next episode, "Deadlock".

[16][26][28][29] Marc Bernardin of Entertainment Weekly wrote, "It felt like Ellen was waging a tiny war within herself, fighting between the lesser angels and greater demons of her nature.

"[27] Jevon Phillips of the Los Angeles Times was less impressed by Ellen Tigh's characterization, calling her "annoying" and the change from the "cool character" of the previous episode "disconcerting".

[31] Alan Sepinwall of The Star-Ledger explained, "This episode makes clear that Cavil didn't invent entirely new personalities for his 'parents' when he imprisoned them in new bodies.

Suspicious of Ellen's sudden reappearance, Adama tasks Dr. Gaius Baltar (James Callis) to submit her blood sample to his newly-invented Cylon detection test.

In "Colonial Day", Ellen shakes hands with terrorist-turned-politician Tom Zarek (Richard Hatch) in public, immediately after Tigh refuses to.

In "Fragged", Ellen assumes that Roslin's confused and slightly delirious state is a mental breakdown, when in fact she is suffering withdrawal from her cancer medication.

Tigh is bitter over Ellen's manipulations, but she is unapologetic, later encouraging him to fire on a ship carrying Lee and Roslin as it flees the Galactica.

Ellen pockets a map to the location where the Resistance plans to rendezvous with an emissary from the Galactica, and the meeting is ambushed by Cylon Centurions.

Tortured by the recent revelation that he is one of the Final Five Cylons, Tigh confers with an imprisoned Caprica Six, but continually hallucinates Ellen in Six's place in "Escape Velocity" and "Sine Qua Non".

His arrival on a devastated Earth in "Sometimes a Great Notion" triggers Tigh's memories of having been there 2000 years before, during the nuclear cataclysm which destroyed the planet.

Aboard their own resurrection ship, the five traveled to the Twelve Colonies to warn them of the danger of artificial intelligence, but without faster-than-light drives, the journey took 2000 years.

Before Cavil can have the information extracted from Ellen surgically, Sharon "Boomer" Valerii (Grace Park), a Number Eight model, helps her escape from the Resurrection Ship.

Ellen and Boomer return to the Galactica in "Deadlock", where rebel Cylon models Two (Callum Keith Rennie), Six, Eight and the last remaining Three (Lucy Lawless) have formed an alliance with the humans.

In "Islanded in a Stream of Stars", Ellen consoles Tigh, who is grieving his lost child, by reminding him that he is the father of millions of Cylons.

They help orchestrate the rescue of Hera from the Cylon "homeworld", a sprawling basestar called The Colony, in the series finale "Daybreak".

In Battlestar Galactica: The Plan, a pair of Cavils monitor a set of resurrection tanks containing copies of the Final Five, two weeks before the cataclysmic Cylon attacks on the Twelve Colonies.

They are evacuated from the planet in a Raptor, and Ellen ends up on the medical transport ship Rising Star, where she slips in and out of consciousness for weeks as she recovers from her injuries.

As the fleet of Colonial survivors, led by the Battlestar Galactica, flees the pursuing Cylon forces, Cavil visits Ellen during the events of "33", and she asks him to find Saul.

1 Favorite Moment in the series, writing "It was so tender, so sweet, so heartbreaking to watch the one-eyed Saul Tigh poison his own wife because she was collaborating with the Cylons—using everything at her disposal, including her body and secret rebel plans, to buy her husband's freedom from toaster confinement.

"[33] Handlen wrote, "That ability to present ambiguity in the midst of intense conflict is one of the show's great gifts, and nowhere is it more apparent than in the death of Ellen Tigh ... the acting on both sides here is gut-wrenching.

I thought this iteration of the character was a bit more like the New Caprica Ellen—shrewd and sharp yet compassionate as well ... Kate Vernon was terrific as the most commanding and shrewd Ellen we've ever seen.

"[26] Reviewing "Deadlock", Sepinwall wrote that "it was alternately hilarious and terrifying to see her shift from playing all-knowing mother to the Cylons to being consumed with her old jealousies at the thought of her husband knocking up one of her children.