Ok so here's what happened:
After the club king and diamond switch, South decided to let it ride to the ten. After all, if the king is onside, he could always finesse later. The jack made the trick and, after a pause, back came a club (the two, confirming East has 5 clubs), ruffed in hand.
South reasoned "East has AK of clubs. If he has the spade ace as well, then the diamond king is definitely going to be offside (East would have overcalled) and I should play for the drop".
So South tried a spade up, which held, opponents showing and odd number of cards. South played the ace of hearts and thought "Well, if spades break I can continue playing them." E/W did have an odd number of cards each all right, only it wasn't 3-3 but 5-1
East ruffed and played back a diamond.
No fear, there is still hope: the diamond king is certainly onside now (with 5 spades to the A109 and a side king West would have overcalled), so South finessed sucessfully. Now all that South needed was the remaining trumps to be 1-1 and diamonds 3-3, so as to disc the last spade on the master diamond.
He tried to cash the diamond ace, but it was not to be. West ruffed and played the spade ace for two down.
Masterful and totally logical compression play. Only the unlucky expert could have gone down