Susan Sarandon gives a committed performance as a mother whose son, a freelance journalist, has been taken hostage by terrorists in the Middle East, but Maryam Keshavarz’s “Viper Club” does not showcase it to best advantage. The drama is earnest and well-meaning, but it never generates the emotional wallop it aims for; even the conclusion, which should be shattering, falls short.

Helen Sterling (Sarandon) is a veteran nurse at a New York hospital emergency room, where she’s a mainstay of the staff, even teaching a young doctor (Amir Malaklou) how to give the ultimate bad news to worried parents in the waiting room while showing support to a mother (Lola Kirke) whose daughter is lying in a coma from which she might never awake. What she hasn’t told her colleagues, including her boss (Adepero Oduye), is that her son Andy (Julian Morris), was seized by insurgents while covering the Syrian civil war and is being held for a huge ransom she cannot possibly pay.

She’s sought help from the government, of course, but none is forthcoming: the FBI agent she’s been conferring with (Patrick Breen) offers only bullet points about not dealing with terrorists and advice about trying to get their demands reduced, and State Department personnel are no more helpful. A congressman brushes her off with a mini-speech about how Andy, by entering Syria against the government’s instructions, had deliberately put himself in jeopardy.

Helen has to look elsewhere, and eventually is contracted by Charlotte (Edie Falco), the mother of a former hostage who knows the workings of a secret group, called the Viper Club, that can help in raising funds and circumvent US policy to make contact with the captors. Two of Andy’s colleagues, Sam (Matt Bomer) and Sheila (Sheila Vand), offer their help as well.

What results is a campaign to raise the money to secure Andy’s release. It involves her talking via Skype with another captive and joining Charlotte to make appeals for contributions from well-heeled prospective donors—with whom, of course, she feels intensely uncomfortable and out of place. Nevertheless the fundraising continues, with a bank of phones eventually replacing direct contact, and it inches toward meeting the terrorists’ demands. It appears, in fact, that Helen’s story might have a happy ending.

Sarandon is clearly the best thing about “Viper Club.” Although the supporting cast—especially Falco and Bomer—contribute strong turns, it’s she who holds the film together as surely as Helen does her own life. Angry, fearful and desperate, Sterling emerges as a complex figure in her capable hands; though perhaps the surname is rather too spot-on, that’s more the fault of Keshavarz and co-writer Jonathan Mastro.

Also problematic is the filmmakers’ dependence on gauzy flashbacks to Andy’s childhood and more recent encounters with Helen, inserted into the main narrative by editor Andrea Chignoli, to demonstrate the power of her maternal attachment. Simply put, Sarandon’s fierce performance is sufficient in itself to show us that, and the rather cheesy ambience of too many of the flashbacks undercuts the integrity of the picture, which otherwise—in Drew Daniels’ gritty cinematography and Javiera Varas’ plain production design—evinces authenticity.

The result is that, apart from Sarandon, “Viper Club” doesn’t transcend the feel of a decent, but hardly outstanding, TV movie. The only difference is that if it were cable fodder, the ending might have been different.