The most tantalising fixture on matchday one of the new Champions League season comes from the Allianz Arena, where kings of Germany Bayern Munich play host to Club World Cup winners Chelsea. These two teams have history - this will be the Blues' first trip back to Bavaria since lifting their first European Cup there in 2012 - but there is an extremely contemporary entity now linking them.
At the back end of the summer transfer window just gone, Bayern were desperately scouring Europe for a versatile attacker to strengthen their forward line. They had swung and missed on Nick Woltemade, who was signed by Newcastle after giving in to Stuttgart's hefty demands.
The search for an alternative led them to Nicolas Jackson, who had been thrust into Chelsea's 'bomb squad' over the summer. This was despite him performing admirably over his two seasons in the first team and emerging as one of their most reliable sources of goals.
At the end of an on-again off-again saga, Jackson signed for Bayern on an initial loan with conditions to make the move permanent later down the line. Though he is still technically an employee of Chelsea, he is eligible to face his parent side on Wednesday due to UEFA rules - a wrinkle that has been to the detriment of the west Londoners before.
Jackson may not publicly be out for revenge and is said to be grateful that he had the opportunity to represent a club of such stature, but he nevertheless has the chance to stick two fingers up at the regime who sent him packing at the first sign of trouble.