Sonia (Jana Raluy) seeks assistance in caring for her ailing husband (Daniel Cubillo) in “A Monster with a Thousand Heads.” (Music Box Films)

In the spirit of “Money Monster” comes another David-and-Goliath tale of villainy laid bare — if not low — by the little man. Like that thriller, about an ordinary Joe who takes the host of a financial-advice television show hostage at gunpoint after losing his nest egg, the brisk yet gripping Mexican drama “A Monster with a Thousand Heads” features an equally angry Everyman — or, in this case, Everywoman — who has been wronged by a corrupt system.

The protagonist here is Sonia (Jana Raluy), a woman whose terminally ill husband Guillermo has been awaiting the approval of a new drug therapy by his insurance company. That company is the “monster” of the title. If we don’t literally see all 1,000 of its heads, we do meet several of them, starting with the brusque receptionist who rebuffs Sonia’s attempt to meet with her husband’s case manager (Hugo Albores) after Guillermo’s condition suddenly worsens, and running all the way to the firm’s chief executive (Emilio Echeverría).

That initial meeting between Sonia and the case manager — the doctor who holds the power to approve or deny parts of Guillermo’s care, and who has been ducking Sonia’s efforts to confront him — does not go well. And when the increasingly desperate Sonia pulls a gun on him, events rapidly spiral out of her control.

Never mind that she really doesn’t want to hurt anyone: All Sonia desires is medicine for her husband, and if it takes threats to get it, so be it. The insurance bureaucracy and the coldly actuarial decisions it makes about life and death is so obstructionist that Sonia soon finds herself doing things that she hadn’t planned.

Although her reaction is extreme, Raluy makes it believable, especially to any American who has been caught in the sometimes Kafkaesque machinery of our own for-profit health insurance. The fact that Sonia’s bewildered teenage son (Sebastián Aguirre Boëda) has come along for this unexpected ride only makes it more convincing. His participation — morphing from that of vocally disapproving bystander to shocked and speechless accomplice — echoes the trajectory of our own investment in the action. It’s surprisingly easy to relate to Sonia’s temporary insanity, especially when we see that it is in response to such an insane system.

Director Rodrigo Plá, working from a spare yet jangly screenplay by Laura Santullo, steadily builds suspense, craftily calibrating subtle shifts in perspective that allow us to alternate, seamlessly, between impartial observers and, as it were, active participants. Once the hostage situation is established, Plá starts incorporating voice-over testimony from what we soon learn is Sonia’s criminal trial. Along with these flash-forwards, he subtly manipulates the camera’s focal points, bringing characters and action in and out of view in ways that heighten both our confusion and our sense of expectancy.

Although there is violence, “A Monster with a Thousand Heads” does not end in the bloodbath that it seems, at times, to be flirting with. That doesn’t mean it’s not tragic. The catastrophe, it argues, is the one taking place off-screen, where we can’t see it and which we are powerless to change.

Unrated. At Landmark’s E Street Cinema. Contains violence, obscenity and nudity. In Spanish with subtitles. 75 minutes.