No Other Choice

Man-su, an award-winning veteran employee of papermaking company Solar Paper, lives happily in luxury with his wife Mi-ri and their two children: Si-one, Mi-ri's teenage son from a previous marriage, and Ri-one, an autistic cello prodigy who won't play in front of her family. However, Solar Paper is bought out by an American company who lay off a number of staff, including a devastated Man-su after he objects to the treatment his subordinates would face. After informing his family, he vows to resume papermaking within three months.

Thirteen months later, Man-su is doing low-paid retail work, having found no success applying for jobs in the papermaking industry. His family is forced to minimize their spending, including rehoming their two dogs to Mi-ri's parents, which causes Ri-one to become distressed and withdrawn. Ri-one's cello teacher recommends her for expensive advanced classes. Unable to pay the mortgage, the family risks having to sell Man-su's beloved childhood home, likely to the parents of Si-one's friend Dong-ho. Mi-ri takes a part-time job as a dental assistant to suave male dentist Jin-ho, who attends the same dance classes Man-su and Mi-ri had to quit in order to save money. Man-su suffers a toothache that he ignores, unable to afford the dental bills.

Man-su attempts to join the successful company Moon Paper, but is humiliated by manager Seon-chul. Wanting his job, Man-su nearly kills Seon-chul using a potted plant but abandons the attempt when he realises killing Seon-chul will not matter unless he is the best candidate to replace him, instead buying a fake job advertisement to identify his competitors. From the applications he receives, Man-su identifies two men whose credentials exceed his own: Beom-mo and Si-jo. Man-su retrieves his father's Vietnam War gun, deciding to kill Seon-chul, Beom-mo, and Si-jo to eliminate the competition.

Man-su first plans to murder the unemployed drunkard Beom-mo. Whilst spying on his house from the woods, he is bitten by a snake and is treated by Beom-mo's dissatisfied wife, A-ra. Man-su and Beom-mo separately discover A-ra's infidelity. Man-su confronts Beom-mo at gunpoint, with Beom-mo mistaking Man-su as A-ra's lover. Man-su, Beom-mo, and A-ra struggle over Man-su's gun. A-ra shoots Beom-mo dead, and Man-su narrowly escapes.

Man-su arrives late to a costumed dance party, where he watches Mi-ri dance with Jin-ho as Man-su was late. Angered, Man-su returns to Beom-mo's residence, where A-ra and her lover have buried Beom-mo and the gun. Man-su retrieves the gun. Back home, Man-su and Mi-ri accuse each other of infidelity before reconciling.

Man-su visits Si-jo at the shoe store where he works, and tricks Si-jo into staying late at work by claiming he wishes to buy shoes for his daughter. He then pretends to have car trouble on the highway where Si-jo passes on his way home. After Si-jo stops to help, Man-su reluctantly shoots him dead, hiding his corpse in Man-su's car.

Meanwhile, Si-one and Dong-ho steal iPhones from Dong-ho's father's store to resell, but the police arrest them. Man-su and Mi-ri blackmail Dong-ho's father, who had used the store for his own infidelity, into having Dong-ho confess that he is the main culprit. Detectives visit Man-su to warn him of Beom-mo and Si-jo's disappearances, which police linked to their common circumstances. While smoking on the roof of the house, Si-one witnesses Man-su in his greenhouse trying to dismember Si-jo's corpse with a chainsaw. Unable to do so, Man-su buries the corpse in his garden, alongside Si-one's stolen iPhones, and plants an apple tree.

Man-su visits Seon-chul's home to befriend him. While plying Seon-chul with alcohol, Man-su is forced to break his own sobriety, leading Man-su to forcefully extract his cavity-filled tooth. Meanwhile, Si-one confesses his concerns to Mi-ri about what he saw, and begins having nightmares about the sound of the chainsaw. Mi-ri digs up the apple tree to find Si-jo's corpse, and calls Man-su with her concerns. Determined to protect his family, and emboldened by Mi-ri's declaration that she is willing to be an accomplice, Man-su refuses to change his path. He then murders Seon-chul by suffocating him and stages it to look like the drunken Seon-chul choked to death on his own vomit. To spare him the truth, Mi-ri tells Si-one that Man-su dismembered a pig and buried it to nourish the apple tree. Man-su returns home, and shares a tense reconciliation with Mi-ri.

Moon Paper decides to hire Man-su to replace Seon-chul. This allows the family to keep their home and reunite with their dogs, reducing Ri-one's antisocial behavior. The detectives visit Man-su, revealing that A-ra has implicated Beom-mo as a gun-owner; they therefore suspect he murdered Si-jo and subsequently went on the run, lifting suspicion off Man-su. Mi-ri and Si-one hear Ri-one playing her cello to the dogs. At work, Man-su celebrates alone in a modern paper mill run by machines instead of workers.