London - After writing the Premier League's greatest fairytale with their astonishing title triumph last season, Claudio Ranieri's side find themselves under siege from big-spending rivals determined to end their reign.
Ranieri's men made a mockery of their status as 5,000-1 outsiders as Jamie Vardy, N'Golo Kante and Riyad Mahrez emerged as genuine stars and carried Leicester to the title a year after they narrowly avoided relegation.
Showing a remarkable refusal to crack under pressure despite their lack of big-match experience, Leicester finished a staggering 10 points clear of second placed Arsenal.
Having lost only three times in 38 league games, no-one could quibble about Leicester's right to call themselves English champions for the first time.
But to some, Leicester's rise was aided by the complete lack of a sustained challenge from any of England's traditional superpowers.
Previous champions Chelsea surrendered the title with a whimper and Arsenal were consistent only in their inconsistency, while Manchester City, Manchester United and Liverpool all underachieved.
Ranieri's side are unlikely to have such an easy ride this time as City, United and Chelsea all look stronger as their new managers splash out on a host of costly signings.
Leicester have tried to keep up with the elite, breaking their transfer record twice within a week as they spent 13 million on French midfielder Nampalys Mendy and 16 million on Nigerian striker Ahmed Musa.
Ranieri has also signed goalkeeper Ron-Robert Zieler, defender Luis Hernandez and winger Bartosz Kapustka.
But Leicester's spending was dwarfed by Paul Pogba's world record 89 million move to United and City's 47.5 million capture of John Stones, while Chelsea paid 30 million to sign the influential Kante.
It is Ranieri's ability to find a replacement for Kante that will define Leicester's title defence.
Kante was a one-man wrecking ball in central midfield as his ferocious tackling and astute interceptions intimidated opponents and set the tone for Leicester's glorious campaign.
With Kante moving on, Ranieri has turned to Mendy and Wales international Andy King to fill the void.
Mendy is likely to be Kante's long-term replacement, but while he gets up to speed with the Premier League, it is the more experienced King who could start in Saturday's opener at Hull.
"If Chelsea bought Kante, it's because he played as two players last season," Ranieri said.
"Now everybody must understand that there is no Kante, so we have to think different and close space quicker. We must be smarter."
King knows it is essential to quickly prove Kante won't be missed, especially given the improved challenges from the top clubs.
"We know we upset the apple cart last season with what we did and we are expecting a reaction from the top teams," King said.
"We have got that, not just from Manchester United, but from Manchester City and Chelsea too. Arsenal as well.
"It isn't something we weren't expecting but we are confident in our own ability, confident in our squad and team here that with hard work we can cause a few upsets again."
Retaining the services of England striker Jamie Vardy, who scored 24 league goals before rejecting the chance to join Arsenal in the close-season, ensures Leicester will retain their spiky edge.
But the additional demands of competing in the Champions League might force Ranieri to tinker with his team more than he would prefer.
The Italian's clever refusal to publicly talk up Leicester's prospects should keep the pressure off his players and he was back to his old tricks when he insisted his first target was simply to avoid relegation.
"I will start with the same philosophy and humility. What Leicester have achieved has been fantastic but now 40 points is the target, then we will see how many months left to the end of the season," Ranieri said.