After an agonizing year-and-a-half spent wondering when we'd see the next season of Dark, Netflix's thrilling sci-fi drama revolving around the interconnected families of a small German town, the series returns for its second season on Friday, June 21. But because the twisty series about the complexities of time travel requires a special sort of mental gymnastics in order to understand its complicated relationships and follow its non-linear narrative, it's completely understandable if, well, you don't actually remember much about Dark. Luckily, you have us. We rewatched all of Season 1 so you don't have to. Here's everything you need to remember about Dark before watching Season 2.

There are four families at the center of the series. On a surface level, Dark follows the Kahnwalds, Nielsens, Tiedemanns, and Dopplers, who are all connected by their intertwined family histories, which can get quite complicated even without the time travel aspect. Here is a handy refresher that explains who everyone is and how they're related to one another.

Everything "starts" when Mikkel disappears. On Nov. 4, 2019, 11-year-old Mikkel Nielsen (Daan Lennard Liebrenz) accompanied his older siblings, Magnus (Moritz Jahn) and Martha (Lisa Vicari), and their friends Jonas Kahnwald (Louis Hofmann), Bartosz Tiedemann (Paul Lux), and Franziska Doppler (Gina Alice Stiebitz) to the caves in the Winden woods. While everyone fled after being spooked by a strange sound, Mikkel disappeared. It's revealed he fell backwards through time, to 1986, where he was eventually adopted by Ines Kahnwald (Anne Ratte-Polle) under the name Michael. He was befriended by Hannah (Ella Lee), whom he later married (Maja Schöne), and together they became parents to Jonas.

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<em>Dark</em>Dark

June 21, 2019 is a significant date in the show's narrative too. The show returns on this date in our lives, but in the show's wibbly-wobbly timeline, it is the date 43-year-old Michael (Sebastian Rudolph), formerly known as Mikkel, hanged himself in the opening scene of the first episode, "Secrets." He left a suicide note with instructions not to open it before Nov. 4 at 10:13 p.m., which is when Mikkel disappeared. The note was found by Ines (Angela Winkler) and later found its way into the hands of 2019 Jonas, who eventually burned it.

Erik Obendorf disappeared two weeks before Mikkel. It's kind of easy to forget about Erik (Paul Radom), who went missing in Oct. 2019. But in the first episode, it is revealed he is being experimented on in a bunker by a stranger, eventually revealed to be Helge Doppler (Peter Schneider), in 1986. The audience finds out very early on that Erik died as a result of the chair experiment, but it is not until his actual body is discovered in 1953, on the future grounds of the nuclear power plant alongside that of another young boy (Yasin), that anyone within the show's narrative knows.

Mikkel and Erik aren't the first young boys to disappear. Thirty-three years before the start of the series, in 1986, Ulrich Nielsen's (Oliver Masucci) younger brother, Mads (Valentin Oppermann), vanished. It is revealed that Mads is the young boy whose body is found in the woods in 2019 after Mikkel disappeared. He was killed by the same chair experiment as Erik and as a result was transported from 1986 to 2019, where his body appeared in the Doppler family bunker. This is witnessed by Peter Doppler (Stephan Kampwirth), who attempted to revive Mads before calling Tronte Nielsen (Walter Kreye), the boy's father, who then moved Mads' body to the woods.

Here's How Everyone in Netflix's Dark Is Connected

The 33-year cycle is what connects it all. Much like the MCU, everything is connected in Dark. As we learn from Charlotte Doppler (Karoline Eichhorn) in Episode 5, the universe returns to the exact same position every 33 years, allowing everything to be the same as it once was in the cosmos. This is why they think everything is repeating itself in 2019. The truth is there is also a wormhole that allows people to travel 33 years into the future or the past, hence the show's Season 1 storylines taking place in 1953, 1986, and 2019.

Andreas Pietschmann, <em>Dark</em>Andreas Pietschmann, Dark

The nuclear power plant is responsible for the wormhole in the caves. Plans for the nuclear power plant in Winden date back to 1953. It's scheduled to be taken off the grid in 2020. In 1986, a blast at the plant created the wormhole that runs through the caves. The radioactive material created by the incident was contained to barrels that were then stored in the Winden caves. Claudia Tiedemann (Julika Jenkins) took over as the head of the plant that same year and had the door to the caves welded shut. By the time Charlotte finds the cave after getting a search warrant in 2019, the barrels are no longer there. Future Jonas (Andreas Pietschmann) finds them in the back of a truck and takes some of the radioactive isotopes contained within them to be used in a device that he believes will create a blackhole that will destroy the wormhole.

The wormhole also runs directly beneath the bunker. The tunnel in the caves that allows people to travel through time runs directly below Helge's bunker. When the tunnel is opened, the energy flows through the room, but it needs to be increased, hence the experiments.

There is a creep known as Noah who preys on children. In Episode 4, Franziska's deaf sister, Elisabeth (Carlotta Von Falkenhayn), meets a strange man named Noah (Mark Waschke) while walking home from school. Later on, in that same episode, her friend Yasin is kidnapped by 1986 Helge and taken to Noah, whom we only see at one age no matter the year, to be a guinea pig in his time machine prototype, aka the chair in the bunker. Noah wants to create a time machine so he can control what happens in the world. In 2019, he recruits Bartosz to his cause by preying on his weaknesses and telling him that he is the good guy while Bartosz's grandmother Claudia (Lisa Kreuzer) and Future Jonas are the enemy.

<em>Dark</em>Dark

Jonas finds out the truth about his father from a future version of himself. Future Jonas sent his past self a box of items he will need when he travels through time, including a futuristic light and the letter Mikkel/Michael had written the day he died that revealed his true identity. After receiving these items, 2019 Jonas used a map of the caves and followed a red string through the caves to find the tunnel and travel to 1986, where he located Mikkel. He was persuaded by the future version of himself — though he did not know who it was at the time — not to interfere with Mikkel lest he erase himself from existence. Jonas then returned to 2019 and realized the full truth about his family. By the end of the season he is in a post-apocalyptic near-future, having traveled an additional 33 years ahead in time.

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Ulrich also travels through time and attempts to kill Helge while he's still just a boy. In 2019, Ulrich follows the elderly Helge (Hermann Beyer), who is said to have dementia, to the caves and travels into the past. He arrives in 1953, where he meets his own father Tronte (Joshio Marlo), who is just a young boy at the time, as well as his grandmother Agnes (Antje Traue). Realizing what's happened and that Helge is involved in the disappearance of the young boys, including the deaths of his brother and son, Ulrich attempts to kill a young Helge (Tom Philipp) in 1953 so he can't kidnap children in the future for Noah. After bludgeoning Helge with a rock, Ulrich drags the boy's body into the bunker, where he eventually wakes up. Ulrich is arrested by 1953 Egon Tiedemann (Sebastian Hulk) for the deaths of the young boys at the nuclear power plant and Helge's disappearance. His photo appears in the paper because of the arrest, and it is found by Charlotte in 2019.

Hannah kind of sucks. This isn't quite the same as everything else, but you need to know that Jonas' mother has a history of being the worst. Not only did she fabricate a lie about Ulrich (Ludger Bökelmann) raping Katharina (Nele Trebs) when they were in high school, but she engaged in an affair with him 2019 and then lied to Katharina (Jördis Triebel) about it, saying she broke it off after Ulrich said he loved her when in reality he ended their liaison when Mikkel went missing. Hannah was so upset by what happened she attempted to blackmail Aleksander Tiedemann (Peter Benedict) into destroying Ulrich by revealing she had a gun and passport that revealed his true identity, Boris Niewald, in her possession.

Andreas Pietschmann and Louis Hofmann, <em>Dark</em>Andreas Pietschmann and Louis Hofmann, Dark

Wöller is working with Aleksander to cover up everything at the nuclear power plant. Worried about what Hannah will do, Aleksander calls Wöller (Leopold Hornung), who works with Ulrich and Charlotte in law enforcement, and asks for dirt on Ulrich. During the call, he asks him what they will do with the trucks that transported the radioactive material from the caves. He tells Wöller when everything has calmed down, they'll bring the barrels back.

Old Helge attempts to kill 1986 Helge to stop the cycle. After his younger self refused to listen to him, the older Helge rammed his car into 1986 Helge's car in a desperate attempt to stop him. The older version died at the scene while the younger survived.

Future Jonas attempts to destroy the wormhole. The adult version of Jonas from the future attempts to destroy the wormhole in the caves using the device that Future Claudia tasked author and clockmaker H.G. Tannhaus to build way back in 1953. It's the same device the Future Jonas asks him to fix when he meets him later on in 1986. Jonas only succeeds in closing the tunnel, not destroying it altogether, which is what Noah told Bartosz would happen. This event also ends up sending 2019 Jonas to a post-apocalyptic future.

Season 2 of Dark premieres Friday, June 21 on Netflix. Season 1 is currently streaming.