For the first time in more than a decade, the Celtics are back in the NBA Finals. It's a time for celebration, sweaty palms and really, really crowded trains at North Station.

It's been a long journey for both the team and fans to get here, and the best part of the year is yet to come. Here are five things you'll need to know ahead of the team's quest to hang an 18th championship banner in TD Garden.

1. The team had a rough start to the season

While it seems obvious now that the Celtics are one of the best teams in the NBA, early on in their campaign, that was far from clear.

The team got off to a now infamous rough start under first-year coach Ime Udoka, with a 20-21 record at the halfway point of the year.

The C's finally started humming the same tune later in the year, finishing the regular season 51-31. Speaking after the Celtics took down the Miami Heat in the Game 7 of the Eastern Conference finals, center Al Horford said he noticed the team started to click around February.

"People were like, 'Well, you guys are beating teams that have guys out, guys are hurt and all these things and I was like, 'It doesn't matter, I'm seeing something different in how we're playing and that's how we're just going to carry it on.' And that's what we've been doing," Horford said.

Forward Jayson Tatum admitted after Game 7 that there were moments when he questioned himself during the early-season slump.

"But, you know, I think you just trust in yourself, trust in the work that you've put in to get to this point and continue to work," he said. "It can't rain forever. Good days was coming. And I felt that we were, whatever it was, one step away from clicking throughout the season. And obviously once we did, we haven't looked back."

2. Now, they face their biggest test yet in the Golden State Warriors ...

The Celtics ran through a gauntlet to get to the NBA Finals, facing the Brooklyn Nets (with Kevin Durant and Kyrie Irving), Milwaukee Bucks (Giannis Antetokounmpo) and Miami Heat (Jimmy Butler). But all of those may pale in comparison to the Golden State Warriors.

The Warriors are like a basketball onion, with layer upon layer of talent. Finals regulars Stephen Curry, Klay Thompson and Draymond Green, who are appearing in their sixth Finals with Golden State, are complemented by Jordan Poole, Andrew Wiggins and defensive standout Gary Payton II, who is rumored to make his way back to the lineup after suffering an injury earlier in the playoffs.

Golden State is as deadly as ever on offense: They lead the NBA in average points scored per playoff game this season, with 114.5 points. They're knocking down 37.9 percent of their three-point shots, a number that gets more important as the postseason progresses. With everything they bring to the table, the Warriors are the favorites to win the series, though just barely.

3. ... but anything is possible

While the Warriors boast an elite offense, the Celtics defense is just as intimidating.

During this season’s playoffs, Boston has averaged just 101 points allowed per game, the second-best mark in the league. The size and versatility of players like Horford, Grant Williams and Robert Williams III give the Celtics an intimidating presence in the paint. Not to mention they have the many talents of Defensive Player of the Year Marcus Smart. Add to that the firepower from Tatum and Jaylen Brown, and this Celtics team — which went 1-1 against the Warriors this season — is nothing to mess around with.

And while this Boston group may be new the Finals scene, Udoka doesn't think his guys are intimidated by the moment.

"We undertand what it is, we know the opponent in front of us and for us, as always. This year it's been business as usual," he said. "Going on the road, not fazed by that at all, so we're really looking forward to it."

4. Ticket prices are silly expensive

If you're hoping to snag a ticket for Games 3 or 4 at TD Garden, God bless your heart and your wallet.

The cheapest seat currently available on Ace Ticket for Game 3 is more than $700. Ace Ticket CEO Jim Holzman said that price could go even higher.

"You never know what's going to happen with pricing, but you may see these go up," he said. "If the Celtics win the first game, you will definitely see the prices go up."

5. History is on the line for both squads

There's a lot on the line for both sides in this matchup.

For Golden State, the Warriors could win their fourth title since 2015, adding to what is already one of the strongest legacies in NBA history, and cementing Curry, Thompson and Green as one of the best trios ever to grace the court.

For Boston, just getting here is a major accomplishment, as the team was the Eastern Conference runner-up in 2017, 2018 and 2020. A Finals victory would place the franchise alone at the top of basketball's Mount Olympus with 18 championship banners — one more than the rival Los Angeles Lakers, who the team beat in 2008 for its last championship win.

Additionally, there's history at stake on the individual level. Ime Udoka could become just the seventh Black head coach to win in the NBA Finals. Al Horford, one of the centerpieces of Boston's run, is the first Dominican player to reach the Finals.

Either way, history will be made. Here's to hoping we'll all get to see some basketball fireworks.

Produced with assistance from the Public Media Journalists Association Editor Corps funded by the Corporation for Public Broadcasting, a private corporation funded by the American people.