• "Squid Game" season one premiered on Netflix three years ago.
• The Korean-language series is one of Netflix's biggest shows ever and was renewed for a second season.
• Here's a recap of everything important you need to remember from season one.

Back in 2021, "Squid Game" premiered, and the buzzy show quickly turned into a global sensation.

The Korean-language Netflix series, created by Hwang Dong-hyuk and starring Lee Jung-jae, is broadly about how adverse financial situations drive people to desperation. In the show, which is set in South Korea, people in heavy debt are invited to participate in a shady game with the promise of a monetary reward. What they don't realize upon joining, however, is that they'll be killed if they lose.

"Squid Game" is one of Netflix's biggest hits ever, to the extent that the streamer even spun it off into a reality series called "Squid Game: The Challenge." Despite the fact that it's endured as a pop culture phenomenon, it's been three years since the first season was released on Netflix.

Ahead of "Squid Game" season two's premiere on December 26, here's everything you need to remember about what happened in season one.

Seong Gi-hun decided to join the games after falling into debt

At the beginning of "Squid Game," Seong Gi-hun is a down-on-his-luck man who, following his divorce, lives with his mother. Hounded by loan sharks and unable to take his daughter Ga-yeong out for her birthday, Gi-hun encounters a recruiter who invites him to participate in a game with a monetary reward.

Gi-hun agrees, and is taken with 455 other players to a mysterious facility. There, he's assigned the player number 456 and encounters his old friend Cho Sang-woo (player 218) who has also fallen into deep debt. Gi-hun also befriends player 001, an old man named Oh Il-nam, and recognizes player 067, Kang Sae-byeok, as a woman who pickpocketed him outside of the games.

Sae-byeok is a North Korean defector attempting to bring her mother to South Korea and provide for her younger brother. Other relevant players include Ali (Player 199), a Pakistani immigrant attempting to provide for his wife and child; Han Mi-nyeo (player 212), a woman who relies on allies to survive the games; and Deok-su (Player 101), a gangster whose comrades sold him out in the outside world.

Guards inform the players that should they win six games, they'll win billions of Korean won.

The first game, 'Red Light, Green Light,' is a bloodbath — but the players still return after.

Gi-hun and the other participants quickly realize that they're in mortal peril when players who fail the first game, "Red Light, Green Light," are immediately gunned down. However, for every player who dies in the games, 100 million won gets added to the prize pot.

Gi-hun and the above players all make it through the first game. The surviving players vote to leave the game without any of the winnings. When presented with the choice outside the game, however, they choose to return. Gi-hun chooses to play after realizing that he can't pay for his mother's diabetes treatment.

Detective Hwang Jun-ho investigates the games, believing they may be tied to his brother's disappearance.

While briefly back in the outside world, Gi-hun attempts to expose the games to the police but fails.

However, detective Hwang Jun-ho notices similarities between Gi-hun's story and the disappearance of his brother, and decides to follow Gi-hun back to the island when he returns to the game. Once there, he poses as a guard. While undercover, Jun-ho discovers a secret organ-harvesting ring led by the game's guards.

Jun-ho eventually finds the games' archives and records, which indicate that his brother was a previous player.

In episode seven, when a group of VIP guests arrive, Jun-ho goes undercover as a waiter to find out more about their identities. After separating one from the rest of the group, he threatens him with a gun and interrogates him about the games.

In episode eight, Jun-ho escapes to another island but is tracked down by the Front Man, the boss of the games, and a group of guards.

The Front Man takes off his mask and reveals he is In-ho, Jun-ho's lost brother, and asks Jun-ho to join him. When Jun-ho declines, In-ho shoots him and Jun-ho seemingly falls off a cliff to his death.

Players begin to form alliances over the next rounds of games.

Gi-hun, Ali, Sang-woo, and Il-nam form one group and are the main focus after the first game. Han Mi-nyeo tries to join Deok-su and begins a sexual relationship with him. Sae-byeok tries to get through the games alone.

The second round is Dalgona, in which players have to cut shapes out of a sugar honeycomb biscuit without breaking it. Sang-woo figures out the game before it starts but tricks his group into splitting up, leading to Gi-hun picking the hardest shape (umbrella). Gi-hun still makes it through after figuring out it is easier to break the shape out by licking the biscuit.

The third game is tug-of-war, in which two teams of 10 pull a rope across a high platform. The losing team's members are pulled over the edge to their death.

Gi-hun and his allies, now including Sae-byeok, split up to recruit five more people, leading to three men and a woman, Ji-yeong (player 240), joining the team. Deok-su betrays Mi-nyeo, kicking her out of his team of men, so she joins Gi-hun's team.

Using clever tactics, Gi-hun's team makes it through tug-of-war despite having weaker people.

There's a secret organ-harvesting sect within the organization.

In episode four, we learn that some of the guards are harvesting the body parts of the players killed in the games to sell on the black market.

They hire Byeong-gi (Player 111), a doctor, to perform the surgery to safely remove the organs. The guards buy his allegiance by giving him the secrets of the next game so he can stay alive, and he uses that information to ally with Deok-su and his group of strong men.

In episode five, the organ smuggling ring falls apart when the guards are unable to tell Byeong-gi what the next game is. He freaks out, kills a guard, and tries to escape. The Front Man tracks down Byeong-gi and the remaining guard and kills them both.

In episode four, the players riot.

After Deok-su accidentally kills another player during a confrontation over food, the players learn they can kill each other outside the games without any consequences and still increase the prize fund.

When the lights go out for bedtime, the players turn on each other. Amid the chaos, Gi-hun and his allies protect Sae-byeok from Deok-su and his cronies. Before there is more bloodshed, Il-nam cries out that everyone should "stop this madness," and the guards intervene and end the riot.

While the guards check the bodies, Jun-ho, still disguised as a guard, approaches Gi-hun and asks him if he has seen his brother, Hwang In-ho. Gi-hun says players don't use names inside the games, so he doesn't know.

Gi-hun bonds with Il-nam.

One night between the games, Gi-hun and his team form a barricade to stop themselves from getting attacked.

While Gi-hun and Il-nam are on watch duty, Gi-hun daydreams about the time he went on strike with his fellow employees at a motor company and was mercilessly attacked by the police.

He then talks about the experience with Il-nam, explaining that they went on strike and barricaded themselves in the company building after the company laid off Gi-hun and a group of employees who had been working there for over a decade.

Then Il-nam falls ill, and Gi-hun looks after him.

Players turn against each other in the Marbles game.

In this game, everyone pairs up. The twist, however, is that their partner will be their opponent: They will play games against each other until one person is the winner and the loser is killed.

Ali and Sang-woo pair up and play a game where you have to guess if there's an even or odd number of marbles in a hidden hand. Ali, who has never played the game before, has a streak of wins, so Sang-woo begs for his life and then tricks Ali into believing they both can win by sticking together. Sang-Woo then steals Ali's marbles and progresses, leaving Ali to die.

Gi-hun and Il-nam play a similar game, but Il-nam begins to lose his memory and focus and wanders off. When they finally play the game, Il-nam is winning until Gi-hun starts to use Il-nam's poor memory to his advantage, lying about the guesses they make. As Gi-hun is about to win, Il-nam reveals that he knew Gi-hun was deceiving him but gives him the final marble anyway. Gi-hun progresses, and Il-nam is seemingly shot off-screen.

Ji-yeong and Sae-byeok pair up, but instead of playing, they open up about their lives. Ji-yeong reveals that she went to prison after killing her abusive father, who killed her mother. At the last moment, the pair play a game where they have to throw a marble nearest to the wall to win all the marbles. After Sae-byeok throws her marble, Ji-yeong deliberately fails her throw. She tells Sae-byeok she has nothing to live for, so she wants her to win and live life to the fullest.

Deok-su makes it through. Mi-nyeo could not find someone to pair with, so makes it through automatically.

Only three characters make it past game five.

Game five is Glass Bridge, where players have to make it across a bridge made of glass platforms. Half of the glass is tempered glass, which could survive the weight of two players, and the other half will break on impact, letting the players fall to their deaths.

The contestants must choose which path is the safe one. They're given an order and Gi-hun, Sae-byeok, and Sang-woo end up near the back of the line.

During the game, Mi-nyeo uses the opportunity to get her revenge, throwing herself and Deok-su onto one of the brittle glass platforms and to their deaths.

After Sang-woo pushes the final player in front of them to his death, Sang-woo, Gi-hun, and Sae-byeok make it across just in time before the remaining glass blows up, but shards of glass stab all three of them.

Sang-woo kills Sae-byeok but dies during the last game.

When they return from the glass bridge, Gi-hun and Sang-woo get into a fight over Sang-woo killing the other player during the glass bridge game. Sang-woo, Gi-hun, and Sae-byeok are given a feast — and at the end, each of them are left with a knife.

Sae-byeok was gravely wounded by a glass shard during the bridge game, so Gi-hun tries to protect her during the night. They promise to look after each other's family members if one of them dies in the next round.

Gi-hun attempts to kill Sang-woo in his sleep, but Sae-byeok stops him and says that he is not a killer. She passes out, and Gi-hun tries to get her medical help. Sang-woo uses this as a distraction to stab Sae-byeok in the neck, killing her.

The final game is Squid Game, where an attacker has to get to a safe area behind a defender. Gi-hun is the attacker, and Sang-woo is the defender. Sang-woo says that he killed Sae-byeok out of mercy — and to prevent Gi-hun and Sae-byeok from voting to end the game.

The game devolves into a bloody fight in the rain, with both men attempting to stab each other. Gi-hun overpowers Sang-woo but doesn't kill him. He moves toward the safe area, but attempts to convince Sang-woo to stop the game with him and leave with their lives.

Sang-woo chooses instead to stab himself, and asks Gi-hun to look after his mother. Gi-hun sees her after he is released from the game, but returns home to learn that his own mother has died.

Gi-hun discovers Il-nam is alive — and not who he appeared to be.

Gi-hun has barely touched his winnings a year after the games. One day, he receives a mysterious card with an address on it.

There he finds Il-nam (Player 001), who reveals he created the games and entered the competition to have fun because he was dying from a tumor. Il-nam also makes a wager with Gi-hun that no one will help an unconscious drunk man lying on the pavement across the street from them. Gi-hun accepts, but Il-nam dies before discovering that he was wrong.

Gi-hun is revived from this encounter, gets a haircut, and changes his hair color. He picks up Sae-byeok's brother, Kang Cheol, and takes him — and a suitcase full of money — to live with Sang-woo's mother.

Gi-hun almost leaves Korea but changes his mind.

Gi-hun prepares to fly to the United States to visit his daughter, but spots the game recruiter at the airport inviting someone else to the game.

Gi-hun chases him down, but the recruiter escapes. Gi-hun steals the invitation card from the new candidate and calls the number on the way to his plane. In-ho answers, and urges Gi-hun to get on the plane.

Gi-hun says that he can't forgive him, and turns back.

"Squid Game" season two premieres Thursday, December 26 on Netflix.