Seong Gi-hun, a divorced father and gambling addict, is introduced as he struggles to make ends meet. He lives with his elderly mother and is deeply in debt, often borrowing money from loan sharks. One day, while waiting for a train, he is approached by a man in a suit who offers him a chance to play a game for money. Gi-hun, desperate for cash, agrees and is taken to a secluded location where he plays a game of ddakji, a traditional Korean game. He loses but is given a business card with a number to call if he wants to participate in more games.

After returning home, Gi-hun contemplates his life and the mounting pressures from his debts. He eventually calls the number on the card, and soon after, he is abducted along with other participants. They wake up in a large, mysterious facility, where they are informed that they will compete in a series of children's games for a chance to win a massive cash prize. However, they quickly learn that losing these games results in death.

The first game is "Red Light, Green Light." The players must cross a finish line while avoiding detection by a giant doll that turns its head to catch any movement. Many players panic and are shot dead, leading to chaos. Gi-hun and a few others, including his childhood friend Cho Sang-woo and a pickpocket named Kwang Soo, manage to survive the first round. The remaining players are horrified but realize they have no choice but to continue.

After the first game, the players are returned to their dormitory, where they are given a chance to vote on whether to continue or leave the game. Gi-hun and several others choose to leave, but upon returning to their lives, they find that the outside world is just as harsh. Gi-hun struggles with his guilt over leaving the game and the reality of his debts. Eventually, he decides to return to the game, believing it to be his only chance for a better life.

The second game is "Sugar Honeycombs," where players must carve out shapes from a honeycomb candy without breaking it. Tensions rise as players try to sabotage each other, and some, like Gi-hun, manage to succeed while others perish. The emotional strain of the games begins to take a toll on the players, and alliances start to form, particularly between Gi-hun, Sang-woo, and a woman named Kang Sae-byeok, a North Korean defector.

In the third game, "Tug of War," the players are divided into teams. Gi-hun's team, which includes Sang-woo and Sae-byeok, must strategize to defeat a much stronger team. They use their wits and teamwork to win, but the loss for the opposing team results in their deaths, further deepening the psychological impact of the games on the survivors.

The fourth game is "Marbles," where players are paired off and must play various games to win each other's marbles. Gi-hun is paired with an elderly man named Oh Il-nam, who initially seems frail but reveals a cunning side. Gi-hun ultimately wins, but the emotional weight of the game weighs heavily on him as he is forced to betray the old man, who he has grown fond of.

The fifth game is "Glass Stepping Stones," where players must cross a bridge made of tempered and regular glass. The stakes are high, and players must make life-or-death decisions as they navigate the treacherous path. Gi-hun and his remaining allies manage to survive, but not without significant losses, including the death of several players who fall to their demise.

As the final game approaches, Gi-hun, Sang-woo, and Sae-byeok are left as the last remaining players. They are informed that the final game will be "Squid Game," a childhood game that involves strategy and physical prowess. The emotional tension escalates as Sang-woo and Gi-hun grapple with their friendship and the desperation of their circumstances.

In the final confrontation, Gi-hun and Sang-woo face off in a brutal and emotional battle. Gi-hun ultimately wins but is left devastated by the loss of his friend. Sang-woo, in a moment of redemption, takes his own life, allowing Gi-hun to claim the prize money. Gi-hun is then released from the game, but he is haunted by the memories of the events and the people he lost.

After returning to the real world, Gi-hun discovers that he has inherited a massive sum of money, but he is unable to enjoy it due to the trauma he experienced. He learns that the games are still ongoing, and he witnesses a man in a suit recruiting new players. In a moment of defiance, Gi-hun decides to confront the organizers of the games, vowing to put an end to the horrific cycle. The season ends with Gi-hun boarding a plane, determined to take action against the games that have caused so much suffering.

At the end of "Squid Game," Gi-hun wins the deadly games but is left traumatized and disillusioned. He discovers the true nature of the game and the identity of the Front Man. In a final confrontation, he chooses to confront the organizers rather than enjoy his winnings. The season concludes with Gi-hun vowing to change the system that led to the games, while the fate of other characters is revealed.

As the final game of Squid Game unfolds, the tension is palpable. Gi-hun, now the last remaining contestant, faces off against Sang-woo, his childhood friend turned rival. The game is a brutal version of the titular Squid Game, where the stakes are life and death. The two men, both emotionally and physically exhausted, engage in a fierce battle, fueled by desperation and the weight of their past.

In a heart-wrenching moment, Gi-hun manages to gain the upper hand. He has the chance to kill Sang-woo, but instead, he hesitates, reflecting on their shared history and the bond they once had. Sang-woo, in a moment of clarity, realizes the futility of their situation. He urges Gi-hun to live and take the prize money to help his daughter. In a tragic turn, Sang-woo takes his own life, leaving Gi-hun as the sole survivor.

With the games concluded, Gi-hun is awarded the prize money, a staggering sum that he initially believes will change his life. However, as he returns to the real world, the weight of his experiences begins to sink in. He is haunted by the memories of the friends he lost, particularly Ali and Sae-byeok, and the moral compromises he made to survive. The money feels tainted, a reminder of the horrors he endured.

In the final scenes, Gi-hun learns about the true nature of the game and the identity of the Front Man, who is revealed to be his brother. This revelation adds another layer of complexity to the narrative, as Gi-hun grapples with the implications of familial betrayal and the systemic issues that led to the creation of the games.

In a poignant moment, Gi-hun decides to confront the organizers of the games rather than indulge in his newfound wealth. He refuses to board a plane to reunite with his daughter, symbolizing his rejection of the life he once sought. Instead, he vows to expose the games and seek justice for the fallen contestants.

As the season closes, the camera lingers on Gi-hun's face, a mixture of determination and sorrow. He is a changed man, burdened by the knowledge of the darkness in humanity and the lengths people will go to for survival. The final shot reveals him turning back to face the camera, a silent promise to fight against the system that allowed such cruelty to exist. The fate of other characters, like the deceased contestants, serves as a haunting reminder of the cost of the games, leaving viewers with a sense of unresolved tension and the question of what justice truly means in a world driven by greed.

In "Squid Game," Season 1, there is no post-credit scene. The final episode concludes with a powerful and emotional climax, focusing on the aftermath of the deadly games and the fate of the main character, Seong Gi-hun. After the intense events, the series ends with Gi-hun making a pivotal decision that reflects his internal struggle and desire for change, leaving viewers with a sense of unresolved tension and contemplation about the themes of the show. The absence of a post-credit scene emphasizes the weight of the narrative and the impact of the choices made by the characters throughout the series.

The number 456 is significant as it represents the main character, Seong Gi-hun, who is the last player to join the deadly games. It symbolizes his position as the underdog, as he is deeply in debt and struggling in life. The number also reflects the total amount of money at stake, 456 billion won, which becomes a driving force for all the players involved.

Ali Abdul, a Pakistani migrant worker, becomes a pivotal character in the story as he represents innocence and loyalty. His backstory reveals his desperate need for money to support his family, which resonates with many players. His bond with Gi-hun showcases themes of friendship and betrayal, especially when Gi-hun ultimately chooses to prioritize his own survival over Ali's, leading to a heartbreaking moment that highlights the moral dilemmas faced by the characters.

The Front Man is a mysterious figure who oversees the games and enforces the rules. His character is shrouded in secrecy, and he is revealed to be the brother of Hwang Jun-ho, a police officer investigating the games. The Front Man's motivations are complex, as he is both a ruthless enforcer of the deadly competition and a product of the same societal failures that led the players to participate in the games.

The game 'Red Light, Green Light' serves as the first deadly challenge in the Squid Game, introducing the players to the brutal reality of their situation. It symbolizes the loss of innocence, as a seemingly innocent children's game turns lethal. The emotional impact is profound as players realize that failure to comply results in death, setting the tone for the psychological horror that unfolds throughout the series.

Kang Sae-byeok, a North Korean defector, evolves from a solitary and hardened individual to a more vulnerable character as she forms alliances with other players, particularly with Gi-hun and Ali. Her motivations are driven by her desire to reunite with her younger brother and escape her traumatic past. As the games progress, her emotional struggles and the weight of her choices become more pronounced, culminating in a tragic sacrifice that underscores the harsh realities of survival.

"Squid Game" is not considered family-friendly due to its intense and graphic content. Here are some potentially objectionable or upsetting aspects that may affect children or sensitive viewers:

1. Violence: The show features extreme violence, including graphic depictions of death and injury. Contestants face lethal consequences for losing games, leading to shocking and brutal scenes.

2. Death: The theme of death is pervasive, with numerous characters dying in distressing ways. The emotional weight of these deaths can be heavy and unsettling.

3. Psychological Tension: The show explores themes of desperation, betrayal, and moral dilemmas, which can be emotionally intense and distressing.

4. Gambling and Addiction: The narrative revolves around gambling and the impact of debt, showcasing the darker side of financial desperation and addiction.

5. Emotional Trauma: Characters experience significant emotional and psychological trauma, which may be difficult for younger viewers to process.

6. Adult Themes: The series includes themes of exploitation, poverty, and the human condition, which may not be suitable for younger audiences.

Overall, "Squid Game" contains mature content that is likely to be upsetting for children and sensitive viewers.