Like keys, Leicester City were totally unique last season. The problem for Claudio Ranieri is rival Premier League behemoths, and their European equivalents, are each in possession of one of the skeleton variety. All locks can be picked; no bonds are sacred.
If Portugal's victory at the European Championship was supposed to be further affirmation of football entering a brave new world, another iconoclastic victory for the collective over the individual, in the Premier League, there is a growing sense the old order are sending in the foot soldiers.
Sound the bugle; the Foxes are being hunted. Armed with open chequebooks and a promise of greener grass, it is a fight Leicester are struggling to counter at present. The Premier League's biggest ever coup could be quelled by August at this rate.
N'Golo Kante has left the building. Riyad Mahrez is expected to be next. Everton have swiped right on Kasper Schmeichel's Tinder profile. Ben Chilwell is supposedly off to Liverpool. Danny Drinkwater is not alone in hinting improved terms wouldn't go amiss, per the Times' Tony Barret and Steve Madeley: "I am not going chasing the club. It is up to them to approach me."
It seems title-winning sides can be dismantled just as quickly as they are assembled.
As ever, Ranieri is dealing with it all with amiable good grace, shrugging it off as though lamenting a late newspaper delivery. After a fleeting 12-month affair, Kante departed for Chelsea with his manager's blessing. The flame may have burned bright for both parties, but there was always a gnawing sense this was a relationship with a short wick.
Kante's replacement, Nampalys Mendy, arrives from Nice on a four-year contract having previously played for Ranieri at the start of his career when at Monaco. He played every game under the Italian during the 2012-13 season en route to winning the Ligue 2 title and is said to be similar in style to Kante. Just so long as he can do the job of three men, he will be fine.
Mendy is one of four signings Leicester have made to date. He is joined at the champions by club-record signing Ahmed Musa, along with Ron-Robert Zieler and Luis Hernandez.
Perhaps it should be worrying for Leicester that the finest player in the Premier League at predicting what will happen before it has actually happened is the first to leave.
Kante, who made more interceptions than anyone else in the top flight last season, according to Squawka, is not a player to let things play out in front of him and then deal with it. It should have come as no surprise when the 25-year-old took control of his future within days of returning from the Euros.
With cold-eyed, ruthless efficiency, he completed his move to Chelsea, leaving Leicester with a shrug, as if he had just been booked for pulling back an opponent on the halfway line. If it's possible to commit a professional foul on a whole football club, this was Kante's on Leicester.
"I am so happy to have signed for one of the biggest clubs in Europe. It's a dream come true for me," he told Chelsea’s official website, having swapped first for 10th.
Maybe he plays squash after work on alternate Tuesday and Wednesdays.
Ranieri has never been a man unable to see the woods for the trees. He sees the bigger picture. He sees football for the game it is. He sees scant reason for tears when a player would rather sign for another club. Leicester may be the Premier League champions, but there has been no change of stance from last season. In February, when quizzed on the future of Mahrez, his response was typically pragmatic.
"We want to keep all our players, we believe in them," he said, via the Guardian's Stuart James. "But if a player comes to me and says: 'Boss, I want to go there because it’s my ambition to go there,' I'll say: 'Go and enjoy and have good luck.'"
A "que sera, sera" mantra is echoed by the club's owners, according to Telegraph writer Sam Wallace:
The attitude of Leicester City's owners, the Srivaddhanaprabha family, has been to make competitive offers for their best talent but not to stand in their way if the individuals in question do not want to stay. France midfielder N'Golo Kante personally requested that the club owner Vichai give a £30 million move to Chelsea his blessing and Kante left the club with the family's best wishes.
I bet he bloody did. Having made the best part of £25-million profit on the player in 12 months, it's a wonder members of the Srivaddhanaprabha family didn't carry the Frenchman to west London on their shoulders, wearing Chelsea shirts emblazoned with "Kante £££" on the back.
From a business perspective it made perfect sense, but titles aren't won on the back of tidy spreadsheets. Just ask Arsenal supporters.
When Kante joined Chelsea, he talked of doing even better. Do you want to tell him, or should I? He will never surpass what he achieved at Leicester. The only way he could have was to stick around and win it again, or make a real impression on the Champions League. He could win the league by thirty points at Stamford Bridge and still it wouldn't hold a candle to his Leicester achievement.
Having secured Vardy down to a new deal worth around £100,000-a-week, it's not as though Leicester can't compete financially. Now is the time for the club's board to signal their intent.
In an industry of perpetual hyperbole and melodrama, Ranieri looks in from afar with a wry smile and an acute sense of the ridiculousness of it all. At the same time, while a lack of a skewered perspective is admirable, those who have enjoyed repeated success time and time again are rarely known for accepting the hand they have been dealt.
As the author of Catch-22, Joseph Heller, once noted: "Destiny is a good thing to accept when it's going your way. When it isn't, don't call it destiny; call it injustice, treachery, or simple bad luck."
Sir Alex Ferguson or Jose Mourinho would be moaning about Kante on their deathbed had they been Ranieri. It doesn't make them better men, but it makes them better managers.
Ranieri is facing his own catch-22 situation at Leicester. Is it better to keep disgruntled players in the hope they will buckle down once the season gets under way, or cut the cord now, and pray a scouting network key to everything they achieved last season will strike gold again?
On that note, it is not just Leicester's players who are attracting attention. According to widespread reports, the club is resigned to losing head of recruitment, and assistant manager, Steve Walsh to Everton.
Credited with the discoveries of Vardy, Mahrez, and Kante, Walsh has emerged as Everton's primary target to complement new manager Ronaldo Koeman, who has in the past worked with a similar setup to great success at Southampton.
According to the Times' Barret and Madeley, Walsh has remained in England while Leicester partake in a training camp in Austria. A mandate to overhaul Everton's recruitment practice and policy is said to excite him.
Walsh, brought into the club by Nigel Pearson, has been a cornerstone of Leicester's success. Time will tell if he has the Midas touch or is just on a hot streak.
Mahrez is also thought to want "another challenge," which is fast becoming a summer-long euphemism at Leicester for "easier challenge."
Does a first-ever Champions League campaign for Leicester City not constitute a meaty enough challenge?
When he arrived at the King Power Stadium in 2014 from the French side Le Havre for £375,000—a lithe winger with a box of tricks, but just as likely to pull a rank final delivery out of his hat as a rabbit—could he ever have imagined the adulation of a sell-out crowd, after winning the Premier League title by 10 points, would not be enough?
To be fair to Mahrez, if Barcelona come calling, let him have his season on the bench with everyone's blessing. Not even Gary Lineker could begrudge him that.
Maybe the American writer Malcolm Gladwell was right, perhaps being an underdog really is a privilege rather than curse, per the Guardian's Oliver Burkeman.
"The fact of being an underdog changes people in ways that we often fail to appreciate," Gladwell said. "It opens doors and creates opportunities and enlightens and permits things that might otherwise have seemed unthinkable."
It had looked to be going so well earlier in the summer when Vardy turned down a move to the Emirates Staidum after Arsenal had agreed to match his release clause. It's easy to sneer at a player lacking sophistication, and an unedifying rap sheet shouldn't be forgotten, yet Vardy's decision to write his own story rather than be a part of someone else's is both ballsy and admirable.
His bond with his manager is touching, too, with Ranieri always happy to espouse his admiration for a player who has taken the long way round to the top, per the Daily Mirror's James Nursey:
I believe in the man. You imagine, he came from a little team and came right to the top, and then a big team wants you but you stay – that is unbelievable.
It is fantastic because Jamie is one of our points of reference. Of course, all his teammates are happy and he gave us a lot of energy to have another good season.
Maybe it is because he started from the bottom and now we are his family. It is the first time in the Champions League too and he wants to stay together.
The charge against Vardy could be he's a modern era Matthew Le Tissier. A need to be loved rather than challenged being the motivating factor in spurning the advances of the prettiest girl in school to stay with the one who thinks they are lucky to have him. Unlike Le Tissier, though, it is unlikely Vardy will turn up for Champions League games next season wearing slippers and a cardigan.
No one as angry as Vardy can ever be truly comfortable.
In any case, I'd argue those vying to leave are motivated by fear as much as they are ambition. The stock of Leicester's players has never been higher. It has been a meteoric ascent out of all proportion with sport's usual parameters of reaching an apotheosis. Is it any wonder there's a band of them now feeling uneasy looking down from the summit, at a watching world intrigued to find out how good they really are?
Maybe Leicester's players aren't so sure about just how good they are, either. After careers largely without applause, which makes them so gloriously relatable, many in Ranieri's squad must read every link to Chelsea, or Barcelona, or Manchester United, or Manchester City, or Arsenal, or Tottenham Hotspur, and think, "this is my one chance, and if I don't move now, I’ll never get the opportunity again."
It's only human to both doubt and want to test yourself at the same time.
Nonetheless, from a neutral perspective, it seems terribly sad we will never see how the full complement of Leicester City's class of 2015/16 would have fared in the Champions League. You'd have thought for one season only they could have parked personal aspiration to one side, to continue a band of brothers story looking set to be cancelled after a single series. Even The Office managed two.
Leicester's title triumph is perhaps without precedent given the vast inequalities of wealth in the modern game, but the closest English football has to an equivalent is Nottingham Forest winning the First Division in 1977/78 having only won promotion the previous season. The following campaign they went on to win the European Cup.
It's a safe bet to say Brian Clough, for all his genius, wouldn't have been able to win Europe's top prize had John McGovern (Kante), John Robertson (Mahrez) and Peter Shilton (Schmeichel) been sold in the intervening summer.
Had Clough been Leicester manager, he'd have locked Kante in the boot room until the opening day of the season. As for Mahrez, he would have been so scared of Clough he'd probably have asked for a pay decrease, what with only scoring or assisting 28 goals last season.
It's not just Leicester's star players, and their respective futures, that require considered thought.
Like a perfect photograph, every element at Leicester is essential. Even the bits most would deem inconsequential. A picture editor looking to crop a photo of Leicester's title celebrations to fit a back page would not lose any sleep at taking scissors to either Leonardo Ulloa or Jeffrey Schlupp. It would still tell the story, just not the whole story.
Both Ulloa and Schlupp, according to reports, have been the subject of sizeable offers that in normal circumstances would probably have been cashed before a medical had been booked. Yet there is nothing normal about what Leicester did last season, and as such, to make every decision with the head over the heart is to endanger what made them so unique in the first place.
Anyone who became implicit in Leicester's story, drawn in by an episodic tale of box-set proportions, will know Ulloa and Schlupp were more than mere substitutes. If Leicester's success really was built on teamwork, the pair were as deserving of a Premier League winners' medal as any of their more feted team-mates.
Ranieri showed he had an alchemist touch last season, he'll need it more than ever between now and the close of the transfer window. Who he keeps at the club will be so much more important than who is brought in.
Beware low flying vultures.