Ozark fans rejoice: The show's fourth season has debuted on Netflix. Planned to be the show's final season, it'll be split into two parts. Seven episodes have dropped as Part 1, with Part 2 coming later this year. That's all good and exciting, but there's a slight problem for viewers like me: It's been two years since Ozark season 3, which in pandemic years equates to at least a couple of decades.

Are you hazy on the details from the past seasons? You're not the only one. Below is all the information Ozark fans will need to remember before streaming season 4. Of course, season 1, 2 and 3 spoilers are below. (No spoilers for season 4, though.)

What's happening with Marty and Wendy?

Ozark is a show filled with cartels, violent gangs, sadistic farmers and dodgy law enforcement agents, yet the relationship between Marty and Wendy Byrde is among the show's most tempestuous.

By the time the first season begins, Marty has obtained video evidence of Wendy cheating on him. They appeared to be headed toward divorce and separation before Marty, with his life threatened, strikes a deal with the Navarro cartel to launder drug money in the Ozarks.

By season 3, Wendy and Marty are seeing a couple's therapist at the behest of their daughter, Charlotte, who had tired of their family's dysfunction. Throughout the season, we see that Marty pays the therapist, Sue, to back him up in his arguments against Wendy. It's in this season that the dynamic of their relationship with the cartel shifts.

Historically it's been Marty who argues for the need to get in deeper with the Navarro cartel in the hopes that they can get their freedom. This is how the couple ends up running a riverboat casino, the Missouri Belle, where they can launder millions each day. But in season 3, he's thinking that they've jumped in too deep and that it's time to cut ties and escape to Australia. With Marty backing out, Wendy begins to take the more proactive role, arguing that the Byrdes can only stay alive and get their freedom if they become indispensable to the cartel.

Marty dishonestly agrees with Wendy to her face while actively sabotaging her attempts at expanding their laundering empire. Helen, the fierce attorney for the Navarro cartel introduced in season 2, finds out about the Byrdes' disagreements and tells Omar Navarro, the cartel boss, who promptly kidnaps and tortures Marty.

As has become a pattern in the show, Marty talks his way out of being killed by making a promise. There's an FBI agent, Maya Miller, who's investigating the Byrde casino. Marty promises to flip her onto their side. Marty survives the ordeal, but his relationship with Wendy is still fractious. They blow up at each other in therapy, with Marty yelling that Wendy has too ambitious a relationship with a drug lord and Wendy countering that Marty's the one trying to flip an FBI agent.

Obviously, Sue the therapist isn't meant to be privy to this information -- so Helen has her killed.

What about Wendy's brother?

If there's one thing that brings Marty and Wendy together in season 3, it's concern about Wendy's brother Ben. Ben is introduced as a hothead who's been heavily medicated into civility and quickly develops a friendship with Jonah Byrde. More important is his bourgeoning relationship with Ruth Langmore.

After a few rebuffs, Ruth accepts Ben's advances and the two spend a night together. Unfortunately, his bipolar medication makes him impotent. To give himself the opportunity to properly fall in love, Ben goes off his meds. It's around this time that Ben finds out what Wendy has been up to in the Ozarks: that she and Marty launder money and, with Helen and the cartel, are responsible for many deaths in the area. That includes Cade, Ruth's abusive father, who we saw was murdered at the end of season 2.

Ben has several outbursts in public, accusing the Byrdes of murderous activity, before Helen has had enough. She tells Navarro that the Byrdes are too much of a liability and that they should be eliminated. As if Ben had not yet made enough of a pariah of himself, he confronts Helen while she's with her daughter Erin. He informs Erin that her mother is in with the cartel and has people killed.

Wendy, seeing that Ben will literally be the death of their family, makes the emotionally wrenching decision to have him killed. She drives him to a restaurant under the guise of reconciliation, but then makes an escape moments before a cartel hitman arrives and disappears Ben.

How this turn of events impacts both Ruth and Jonah will be a key part of season 4.

And there's a cartel war?

Yes. The Navarro cartel, with which the Byrdes are associated, is at war with the Lagunas cartel. Their war is established in the fiercest episode of season 3 and escalates throughout. Halfway through the season, Navarro instructs the Byrdes to inspect and buy a horse farm in Kentucky. After Wendy makes a generous offer to the farm's owners, it's revealed to be a ruse. Navarro didn't want the farm, just access to its prize horse -- which happens to be owned by the Lagunas. His men find and castrate the horse. When Wendy objects to his subterfuge, he says he's in a war and the Byrdes are tools he can use in whichever way he pleases.

The high point of the cartel war comes in episode 6. The Byrdes have an agreement with the Kansas City mob and its head, Frank Cosgrove, where in exchange for a cut in the casino's laundering activities, the mob helps move money around for the Byrdes. That's literal: They transport shipments of cash to Ruth for the casino.

Hitmen from the Laguna cartel ambush one such money drop, which takes places outside the city. Several members of the Kansas City mob were killed, but Ruth escaped thanks to the intervention of Ben, Jonah and Jonah's drone, which Jonah had set up to help monitor the Byrde house. In short, Ben and Jonah helped save Ruth's life.

The drone is key here. Marty submits the footage shot from it to the FBI's agent Miller, who is actively investigating him, which gets several Laguna cartel members arrested. This is important later.

Ruth was nearly killed by the Cosgroves

Throughout season 3, Ruth has an increasingly antagonistic interactions with Frank Cosgrove Jr., son of the mob boss. Remember that the Cosgroves are in business with the Byrdes, as the casino couldn't be constructed without the mob's blessing. Cosgrove Jr., thinking himself untouchable, begins loan sharking at the casino, and his men openly flout Ruth's money delivery orders. In one scene, Cosgrove Jr. starts a kerfuffle and Ruth pacifies him by tossing him off the casino riverboat.

Retribution comes swiftly where, in a confronting scene, Cosgrove Jr. ambushes Ruth outside of the casino and beats her to near death. As a result, Marty cuts the Cosgroves out of the casino. In hospital, Ruth demands that they have Cosgrove Jr. killed, but Marty, keenly aware of the FBI investigation of him and his casino, says that's not workable. This creates a rift in Ruth's relationship with Marty, as she feels undervalued and underprotected.

This rift opens wide when Ruth finds out that Wendy had Ben killed. Upon that discovery Ruth, furious at Wendy for the deaths of both her father, Cade (season 2), and her lover, Ben (season 3), cusses out Wendy and quits working for the Byrdes.

What's the deal with Darlene?

Who knows.

Darlene Snell ended season 2 by fatally poisoning her husband, Jacob. In season 3, she becomes a guardian figure for Wyatt Langmore, the recently estranged cousin of Ruth. Wyatt is mad at Ruth for killing his dad -- fair enough. To recap: In season 1, Russ and Boyd Langmore tried to kill Marty and steal the millions he was laundering, but Ruth, realizing she was likely to be blamed for the crime, set up an electrocution trap on the docks by the bar Byrde owned, which Russ and Boyd were killed by. Wyatt found out that Ruth was behind his father's death at the conclusion of season 2 and, as season 3 begins, we see that Wyatt has escaped the Langmore dwellings and is now staying in empty houses he breaks into.

After getting arrested for illegal entry, Wyatt rejects Ruth's offer to pay bail -- but accepts a mysterious offer from Darlene. In exchange for bail, Wyatt will work for the Snell farm. Darlene and Wyatt quickly begin a romantic relationship, with Wyatt helping to take care of Zeke, Darlene's adopted baby. (Zeke was Pastor Mason's, but Mason snapped and kidnapped Wendy in season 2, which led to Marty killing him and the Byrdes taking Zeke. Darlene, determined to foster a child, got the Byrdes to hand Zeke over to her after she threatened Jonah by kidnapping him and giving her a haircut at the Snell ranch.)

As season 3 ends, Darlene tries to win the services of Ruth shortly after she resigned from the Byrdes. To prove her loyalty, Darlene finds Frank Cosgrove Jr., the guy Marty didn't want to harm, and shotguns his testicles off.

How did season 3 end?

After the Byrdes couldn't control Ben, Helen advises Navarro that the Byrdes should be eliminated. Aware that Helen was campaigning for their doom, Wendy tries to one-up Helen by proving the Byrdes' value to the cartel. This eventually ends up with Marty supplying the FBI video proof of the Laguna cartel's murderous attack, in which Ruth was narrowly spared. This leads to the arrest of several Lagunas.

Season 3 ends with Helen escorting the Byrdes on a private plane to Mexico for an urgent meeting with Navarro. In the final scene of the season, the Byrdes arrive with Helen expecting the worst. After a tense moment, one of Navarro's men executes Helen on the spot. Navarro hugs the Byrdes as the credits begin the roll.