They opened one club, partner merely overcalled, after an aggressive evaluation, I first cuebid, then put my partner in the spade game
When a club went to the Ace, and a diamond was returned like an express train, partner took the reasonable line of going up Ace of diamonds and played the King of clubs, pitching a diamond. There was no recovery from here.
This is a curious hand where you need (following the assumption that all the diamonds are bunched up on declarer's left,) to maintain the 8 of diamonds and pitch a heart, because you need the suit-establishment power D8 to set up the D suit for one loser, after trumps are drawn. Therefore the right discard on the King of clubs is a HEART, not the precious D8. Watch. HEART pitch on the King of clubs, spade ace and spade. Now either opponent can arrange to win this trick, although in practice W likely will, and tap dummy with the Queen of clubs. (It makes no difference if W unblocks SK and E wins, and a heart forces north to trump). The next trick is to the Diamond 8 or the diamond 8 led around. North now has TWO trump at least left, to ruff out and set up the diamonds)
So this is a peculiar hand where the suit establishment possibility of AQJ9x opposite 8x indicates it is better to develop this suit with the help of the 8 rather than discard the 8 on a established winner, and get tapped out!!