The hockey gods have blessed us with a Flyers-Penguins playoff series for the first time since 2012: praise be to the hockey gods.

Even casual sports fans know that postseason hockey, particularly overtime postseason hockey, is a relentless assault on the human nervous system. It’s not ideal that they play most of the games at night, because it’s tough to go to sleep after three hours of convulsion-inducing anxiety. The games should come with a warning: Do not operate heavy machinery if you’re consuming playoff hockey.

Penguins-Flyers is the Cadillac of playoff hockey series—about as nasty a rivalry as you can get without any underlying history of political or sectarian violence. It’s particularly dear to me, a person who (in the interest of full disclosure) grew up in South Jersey, learned to skate at the Flyers’ practice rink, and frequently sleeps in a Daniel Carcillo Flyers shirsey. But even those of us who grew up rabid NHL fans are pragmatic about hockey’s place in the American sports hierarchy, so in advance of this upcoming first-round matchup, here are some people, places, and concepts you should familiarize yourself with in order to enjoy this series to the fullest.

Pennsylvania: A large U.S. state, home to one large city on each end, with the world’s most annoying toll highway and a bunch of people who drive with their high beams on all the time. On the west of the state is Pittsburgh, a city of potato worshippers with a thing for yellow hand towels. In the east, Philadelphia, a city where potatoes are made of coconut and cream cheese. Philadelphia’s sports culture is on the rise, and carries a reputation for human sacrifice, not unlike ancient Carthage. Each city has been home to an NHL franchise since 1967.

Line brawl: A week before the end of the 2012 NHL regular season, the Flyers beat the Pens 6-4 in Pittsburgh, in a game most remembered for events that took place near its conclusion.

With a little over a minute left, Pittsburgh center Joe Vitale laid out Flyers forward Danny Briere, sparking a stoppage of play in which each player grabbed someone from the other team and some of those pairs devolved into bouts of fisticuffs—a line brawl, in hockey parlance. These are fairly common in the NHL, even with fighting on the wane, but what made this line brawl special is what then-Flyers coach Peter Laviolette did. Laviolette—who endeared himself to Philly fans early in his tenure by coaching an aggressive, up-tempo style of hockey, leading the team to the 2010 Stanley Cup Final and looking like a corrupt police detective in the process—tried to climb over the boards and beat up his Pittsburgh counterpart, Dan Bylsma. (Flyers assistant coach Craig Berube, who racked up more than 3,000 penalty minutes in his own NHL career, remained the only calm person in the building.)

That line brawl presaged a first-round series that can only be described as six games of orgiastic violence and goalscoring. That matchup laid a swath of destruction across the mid-Atlantic that proved, definitively, that humanity has not fully evolved past its baser instincts.

Playoff beard: Hockey players are obsessed with toughness and manhood, and many of them choose to demonstrate that “toughness” and “manhood” in the postseason by not shaving until their team is eliminated. Here are the Penguins’ two best players, Evgeni Malkin and Sidney Crosby, who have between them grown one playoff beard.

“The best player in the world”: For about a decade, that referred to Crosby, who in 13 seasons has won three Stanley Cups, two scoring titles, two Hart Trophies for league MVP, and two Olympic gold medals. Even as Edmonton’s Connor McDavid ushers in a new generation of talent, Crosby is still one of the best all-around centers in the game—he’s a point-a-game scorer and a bigger physical presence than his 5-foot-11 frame would suggest. And he’s still only 30 years old.

This is the fourth Flyers-Penguins playoff series for Crosby, Malkin, and Penguins’ defenseman Kris Letang. The only Flyer who’s been around for more than one is their captain, Claude Giroux. Giroux’s first career playoff action came in a first-round loss to Pittsburgh in 2009, when he scored five points in six games as a 21-year-old rookie. Three years later, he broke out for 14 points in the six-game Gotterdammerung of 2012 while also fighting Crosby in Game 3, then leveling him off the opening faceoff in Game 6 before scoring 32 seconds into the contest.

That performance inspired Laviolette to call Giroux the best player in the world, which turns out not to have been true at any point apart from those six games in 2012.

But any series involving Crosby invites comparisons to opposing stars, and Giroux, who just turned 30 himself and is in his sixth season as Flyers captain, is an appropriate foil. After slowly declining from his 86-point performance in 2014—a performance that earned him his only top-three Hart Trophy finish—Giroux has found new life playing alongside center Sean Couturier this season. He’s registered career highs in goals, assists, and plus-minus, and recorded the first 100-point season by a Flyer in more than 20 years. The title of best player in the world won’t be at stake in this series, but Giroux vs. Crosby is a headline player-vs.-player rivalry.

Evgeni Malkin and Phil Kessel: The Penguins are so tough in the playoffs because of their star power, but also because of their depth. Head coach Mike Sullivan has won two Stanley Cups in two tries because he’s essentially eschewed the idea of a checking line, preferring to play fast on all four lines and wear opposing defensemen down. But more than that, Crosby isn’t their only superstar. For the past decade, the Penguins have entered almost every game with the two best players on the ice: Crosby and Malkin.

Malkin, unlike Crosby, is gigantic. His listed dimensions of 6-foot-3, 195 pounds, don’t do him justice—those measurements must’ve been taken when he was a teenager, and during a time of famine. When Crosby missed 60 games in the 2011-12 season, Malkin won the scoring title and the Hart Trophy. And while most teams have one go-to defensive unit capable of slowing down a superstar center, almost nobody has two.

And on the Pittsburgh’s third line sits Kessel, a 30-year-old goober from Wisconsin who happens to be a preternaturally gifted scorer. Best known as the older brother of U.S. Olympic gold medalist Amanda Kessel, Phil’s quite a player in his own right. He has three point-per-game seasons under his belt, including a career-high 92 points this year, and he hasn’t missed a regular-season game since October 2009. He led the team in scoring during the 2016 playoffs and finished third behind Crosby and Malkin last postseason. And yet because he’s balding, American, and putzy, he gets a bad rap in certain circles of the hockey world.

For instance, Kessel arrived in Pittsburgh three years ago after he was run out of Toronto for being the only good player on a dogshit team. On his way out, Toronto Sun columnist Steve Simmons penned a now-infamous column (that was almost certainly untrue) about Kessel’s affection for hot dog carts. After winning his second title with the Penguins, Kessel spent his day with the Stanley Cup on the golf course, eating hot dogs out of hockey’s most sacred vessel. It’s part of a larger pattern of Kessel exacting revenge for perceived slights by living well—after being left off the World Cup team in 2016, Kessel subtweeted USA Hockey after Canada played the Americans off the rink in the group stage.

Just sitting around the house tonight w my dog. Felt like I should be doing something important, but couldn't put my finger on it. — Phil Kessel (@PKessel81) September 21, 2016

Even as one of the most vitriolic Flyers fans you’ll ever meet, I have a grudging respect for many of the Penguins and their accomplishments. But I will go to fucking war for Phil Kessel. He is a national treasure and must be defended at all costs.

Sean Couturier: In 2012, while Giroux faced off against Crosby’s line, the task of slowing down Malkin and James Neal—who’d scored a combined 90 goals in the regular season—fell to then-19-year-old Sean Couturier. For the first three games, Couturier (6-foot-3 and about 110 pounds at the time) and his linemates held Neal and Malkin to just two goals combined—resulting in three Flyers wins. But during garbage time in Game 3, a frustrated Neal tried to solve his problem by decapitating Couturier with an open-ice hit away from the puck. (Couturier said he was “seeing stars” after the hit but was back for Game 4.)

Nowadays, Couturier plays with Giroux, and he’s more than doubled his career high in goals, and raised his career high in points from 39 to 76. But this time, someone else is going to be tasked with stopping the Malkin Line.

Ghost Bear: Or Shayne Gostisbehere, who, along with Ivan Provorov, makes up the core of the Flyers’ defense. Gostisbehere scored 17 goals as a rookie in 2015-16 before his shooting percentage cratered and Flyers coach Dave Hakstol (who has an ostentatious mistrust of young players) started scratching him. But he’s bounced back this season, finishing fourth in the league in scoring among defensemen with 65 points in 78 games and becoming the first Flyer defenseman to break 60 points since 1994. Most of Philadelphia’s offense comes from Giroux, Couturier, and Jakub Voracek, and Gostisbehere helps mitigate the team’s lack of bottom-six production.

Radko Gudas and Patric Hornqvist: Most of the goons and pests of the 2012 team have moved on, and the league’s gotten a lot less goony in general since then. But not so much less goony that we can rule out Gudas or Hornqvist boarding or slew-footing someone and inciting a line brawl.

Pelle Lindbergh, Ron Hextall, and Sergei Bobrovsky: The Flyers won their only two titles in 1974 and 1975, in large part because they had Bernie Parent, the best goalie in the world. In 1985, they went back to the Stanley Cup Final, thanks in large part to 25-year-old goalie Pelle Lindbergh, who won the Vezina Trophy that year as the league’s top netminder. That fall, Lindbergh died in a car crash, but two years later the Flyers developed another young Vezina winner, Ron Hextall, who took the team back to the final in 1987 and won the Conn Smythe as postseason MVP, despite the Flyers losing to Wayne Gretzky’s Oilers in seven games.

Since then, Flyers goaltending has been defined by its ineffectiveness. (The Galaxy Brain take is that Bobby Clarke, Parent’s teammate from 1969 to 1971 and 1973 to 1979, was so motivated by professional jealousy that when he became GM of the Flyers for the second time in the 1990s he went out of his way to avoid signing a franchise goaltender in an attempt to prove that you could win a title without one.) Rookie goalie Brian Boucher caught fire in the 2000 playoffs—during the second-round matchup with the Penguins, he went more than three consecutive hours of game time without allowing a goal, including most of a 2-1 five-overtime siege in Game 4—but that was an anomaly.

In fact, the lasting memory of the 2012 series, apart from the violence, was a universal failure in net. The Flyers had tried to solve their goaltending problems before the season by throwing $51 million at world-class weirdo Ilya Bryzgalov, who posted a save percentage of just .871 in the first round of the playoffs. And Penguins goalie Marc-Andre Fleury was even worse. Fleury, the no. 1 overall pick in 2003, won three titles during his time with Pittsburgh, but nevertheless developed a reputation for going to pieces in the playoffs and posted an .834 save percentage in the 2012 postseason.

In Game 4 alone, the Penguins put 10 goals past Bryzgalov and his backup, Sergei Bobrovsky. That’s the only playoff game since 1990 in which a team’s put up double-digit goals. Bobrovsky, who’d had a promising rookie season before Bryzgalov showed up, was shipped to Columbus that offseason. Since the trade, he’s won two Vezinas of his own and in that time has the highest save percentage of any goalie with at least 200 games played. Meanwhile, Hextall took over as the Flyers’ GM in 2014 and eventually assembled an uninspiring goalie trio of Michal Neuvirth (frequently hurt), Petr Mrazek (inconsistent), and Brian Elliott (sometimes hurt, sometimes inconsistent). Stuff like the Bobrovsky trade is enough to make you believe in curses.

Jake Guentzel: One annoying thing about Crosby is that in the past couple years he’s developed the ability to turn any beer leaguer off the street into a top-line winger. Last year, Guentzel, a rookie third-rounder out of the University of Nebraska Omaha, scored 33 points in 40 games playing mostly with Crosby in the regular season, then scored 13 goals—more than anyone else in the league—during the playoffs. I’m very eager to see which rookie I’ve never heard of will turn into Patrik Laine in this postseason once he starts getting playoff minutes on Crosby’s wing.