PARIS -- Heartache and evolution hangs heavy in the expectant Parisian air as the All Blacks and Ireland, one of rugby's great modern rivalries, prepare to collide in a Rugby World Cup quarterfinal for the ages.
Peel back the layers on a sudden death showdown that will either send the world's top ranked side or the three-time World Cup winners packing and there's enough jeopardy to fill the Louvre.
Ireland's relationship with the All Blacks first tilted on its axis in 2016 when Joe Schmidt inspired their maiden win against New Zealand in Chicago.
While that breakthrough, and the maiden victory on Irish soil two years later, altered perceptions, Ireland then crumbled when it mattered most against the All Blacks to fail to progress past the 2019 World Cup quarterfinals.
Since then, though, the dynamic has further shifted, perhaps definitively, in Ireland's favour.
Four wins from their last six Tests - three from the last four since their World Cup exit - proves Ireland have had the All Blacks' number. They don't fear the All Blacks anymore. That's partly why Ireland start favourites to hand the All Blacks their equal worst World Cup result this weekend. Cue New Zealand on tenterhooks.
Retrace the footsteps on Ireland's last three victories over the All Blacks -- in Dublin, Dunedin and Wellington -- and you unearth a once-in-a-generation side that intrinsically knows each other and their game.
Schmidt's seven-year tenure laid the foundations for this Irish team. Andy Farrell has since, in the last four years, significantly advanced and evolved Ireland to the ruthlessly efficient, accurate, highly organised beast they are today.
Belief is a powerful commodity. Last year's maiden victory on New Zealand soil, and subsequent first series win, was a juncture on which Ireland's belief soared. Those achievements marked the start of Ireland's now 17-test unbeaten surge but, more importantly, that series represents their most poignant brick in the wall for World Cup optimism.
Once a team bogged down and burdened by the crippling weight of history, Ireland under Farrell have morphed into a supremely confident, cohesive unit.
As hoodoos loom - Ireland have never progressed beyond the World Cup quarterfinals and no Tier 1 nation has won more than 18 Tests in succession - Farrell and his band of headstrong men appear undaunted by the task of smashing further glass ceilings.
In New Zealand last year, Ireland proved the All Blacks' kryptonite. Their organised defence swarmed and suffocated. Their supreme breakdown work stunted the All Blacks at the source. And their meticulous attack targeted and picked apart the All Blacks props two phases ahead.
While that series proved pivotal for Ireland it also rocked and reshaped the All Blacks for the better. Assistant coaches John Plumtree and Brad Mooar -- along with several regular players -- were cast aside as Ian Foster fought to successfully save his tenure.
In came influential forwards coach Jason Ryan, who has since markedly improved the All Blacks maul defence and set-piece platform, and Schmidt.
After seven years (2013-2019) leading Ireland Schmidt knows their senior players intimately. Such insights are gold at this defining juncture but Schmidt's value to this point has been the demanding detail he's brought to the All Blacks' breakdown, attack and skill work.
Last year Ireland shone a spotlight on the All Blacks glaring weaknesses to embarrass them at home. It forced the All Blacks to absorb harsh lessons and instigate sweeping changes as they attempted to rebuild for the World Cup.
Now on that pinnacle stage the All Blacks are a world removed from last year's series. The team that runs out at Stade de France on Saturday night could feature eight starting changes. Many of the All Blacks' former weak points, particularly the set-piece and maul defence, would now be considered strengths. That in no way diminishes the task of challenging the world No. 1 in a knockout match, but it does offer perspective about the All Blacks' evolution.
"Last year matters in the sense of taking the lessons but I believe we're a totally different team to July last year," All Blacks halfback Aaron Smith said. "We've got new coaches. As a group that series really galvanised us. I can't wait for Saturday."
While there's a level of mutual respect the All Blacks don't fear Ireland, either. They know the influence cards had -- a red in the second and yellow in third Test -- on last year's defeats. And while they were at a low ebb, the All Blacks were the last side to defeat Ireland.
From Dane Coles to Beauden Barrett, Smith, Rieko Ioane, Foster and Ryan, the All Blacks have consistently stated this week they want Ireland in this quarterfinal. The hurt, frustration from last year lingers. They crave a cathartic chance to settle the score.
"We learnt a lot during that series. It was a challenging time - some of the most challenging times we've faced as an All Blacks team and personally, losing a series in our backyard," Barrett said. "We know the beast Ireland are and if you allow them to dictate up front and play the way they want they're a tough team to stop.
"Ireland in the quarterfinals it's going to be great because there's a lot of us who are pretty keen to get one up on them and are still hurting from what happened last year.
"We're not looking past this quarterfinal. It's our final. It's against Ireland, the No 1 team, that's exactly how we want it."
The ever-honest Coles, one of six veteran figures potentially preparing for his last Test, encapsulated the All Blacks' mindset.
"There's a few scars with us losing to them, you can't get away from that fact. It would be a really good opportunity to play them. I know everyone in this team, we're looking forward to it," Coles said.
"The All Blacks were the benchmark for a long time so to come up short in your home country it was more than a kick in the guts. Every time you lose in the All Blacks jersey it leaves a scar so we had to look at ourselves and try get back to the top. They've been the benchmark for a few years now so you want to play the best teams. There's no shying away from that it's a Rugby World Cup."
Stage set, then. A new-age Ireland against the reformed All Blacks.
What more could you ask for?