Chelsea want to sign Sergio Agureo. Athletico Madrid want to let the Argentina striker go.
But Madrid want £40m - Chelsea don't want to pay that amount.
So meetings after meetings have being held between representatives of all parties to try and trash out a compromise.
Ultimately the decision to buy the player rests with Roman Abramovich. But does Roman rate the player at £40m?
Chelsea have a football executive - Frank Arnesen and his advisors are the main decision-making people in this. Chief executive Ron Gourlay will say his bit.
His perspective will be one of the commercial viability of the player and if the business can afford him.
Arnesen's role is one from an actual ability/squad building perspective.
When all sides agree then the matter is sent up to Roman for consideration and if the man says "yes" then it's all systems go.
Clearly Aguero is a player not in the Kaka or Messi class - but a very good player. Will he be happy to play a supporting role to Drogba and Anelka?
That is the area where the club need to invest time and energy. They need to understand the player. Arnesen and Gourlay are only part of the solution.
The club needs to know what a player is like - not just his ability or commercial potential.
Too much money has being wasted on players who have not fitted in - Sheva, Veron etc - multimillion-pound mistakes the club were willing to accept.
But no more. Roman is not prepared to lose that amount of money again.
That's why he is currently balking at the £40m price tag for Aguero, according to a club source.
Chelsea have to buy and buy big and well during the January transfer window.
This is their only guaranteed chance to wheel and deal.
KatutaGate means the appeal again their transfer ban will probably be heard next spring. If it's rejected, Chelsea won't be able to buy in the summer.
So, the club can, if it decides to put their summer transfer budget into this window.
They won't get the very, very top-class player, but they might just get an Aguero.