[3] Its plot follows a troubled mother and her adolescent daughter who find themselves stranded at night on a country road with a malicious creature hunting them.

Kathy (Zoe Kazan) is driving her teenage daughter Lizzy (Ella Ballentine) to her father's house as it is his turn for custody.

Tired of taking care of her abusive, unstable, alcoholic mother, Lizzy makes it clear she wants to live with her father permanently.

A severely mauled Jesse crawls out of the woods, only for a monstrous creature to drag him under the tow truck and eat him before Kathy can help.

Now aware that the monster is scared away by bright light, Kathy uses her lighter to make a torch and tells her daughter her plan.

A distraught and enraged Lizzy, now determined to avenge Kathy's death, uses her mother's lighter and a spray can from the ambulance to set the monster ablaze.

Commenting on his aspirations writing the screenplay, Bertino stated: I did decide I was going to push myself to explore different kinds of fear, but finding my window in is always going to be the victims first.

[6] Commenting on committing to the project, Kazan stated that she was "really captured by the story of these two people, especially of the mother really struggling against her worst behaviors to protect her child.

The website's consensus reads: "The Monster uses its effectively simple setup and a powerful lead performance from Zoe Kazan to deliver a traditional yet subtly subversive—and thoroughly entertaining—horror story.

[19] Manohla Dargis, in her review for The New York Times, compared the film to other horror stories about "monstrous motherhood" released for art house and multiplex crowds, saying The Monster was "cleverly pitched somewhere in between."

Of the two main actresses and their roles, Dargis noted "Ms. Kazan gives her lungs a workout, and while she’s more persuasive as a scream queen than as a mother, she and Ms. Ballentine get the job done.

"[20] Justin Chang of the Los Angeles Times praised Bertino's establishment of suspense, writing that he "doles out the jolts with a judicious hand.

"[21] Brian Tallerico of RogerEbert.com praised the creature effects, likening to those in Alien, as well as Kazan's performance, which he wrote "captures the truth of the moment in which Kathy struggles.

"[22] The Hollywood Reporter's Justin Lowe wrote that the film "reduces primal fear to its fundamental elements," praising cinematographer Julie Kirkwood’s "ominously prowling camera and sometimes deliberately murky lighting consistently amplify tension by obscuring the threat lurking just beyond the frame.