Questionable Slam

I am in Colorado Springs, playing in a Swiss game with a partner I just met.  We took about 20 minutes filling out a card, and agreed to play 1430 Keycard.  We were not playing Kickback (bidding the suit above trump as Ace Asking once a fit was established), per se, but he did say that he sometimes would use it when obvious (whatever that means!).  We also agreed to play Exclusion Keycard (jumps to 5-level ask for keycards in suit other than the one bid.) We were scrambling around, trying to find a fourth player for our team, so we never quite finished the conversation.  This came back to get us.

Vulnerable, partner and RHO passed and I opened 2NT with

♠ K J 3
♥ A K 6 5 2
♦ A 7 4
♣ K Q

Partner bid 3C, Puppet Stayman, asking for a 4- or 5-card suit.  I bid 3H, showing my 5-card suit, and he went in the tank and pulled out the 4S bid.  Clearly it would not be natural (he would have transferred me to spaded over 2NT if he had spades).  Exclusion?  Seems doubtful, since not at the 5-level.  It seems that 3S would be a cuebid, but maybe my partner wasn't sure it would be forcing, so I decided 4S must be a cue-bid, showing interest in slam.  I bid 4NT to ask about keycards. He bid 5C, showing one.  I bid 5D to ask about the trump Queen, and he jumped to 6H.

My partner meant 4S as Keycard!  He thought 4NT showed 4 keycards, and he meant 5C as the Queen Ask.  My 5D evidently said I had it, so he jumped to 6H, believing we had all 5 keycards and the trump queen (but evidently thinking that we shouldn't be in 7H with only 31-32 HCP). 

I got a small club lead, and here is what I saw:

♠ Q 8
♥ 7 4 3
♦ K J T 8 2
♣ A J 5

♠ K J 3
♥ A K 6 5 2
♦ A 7 4
♣ K Q

I must lose a trump trick on any layout, so how do I avoid losing the spade Ace?  I need some luck.  I need to conceal my club King, so that the person who wins the trump trick will continue clubs (assuming they don't have the Spade Ace).   I can't give up the first heart trick, though, because I run the risk of the the person with the Ace overtaking partner to cash that Ace).  My hope is to throw all three spades away, two on the diamonds and one on the long club.

So, I win the first club in dummy with the Ace and then drop the Queen from my hand.  Now, this suggests I have a singleton at first glance.  But, it would also be a reasonable false-card if I held Qx.  Then I play the Ace of Hearts and a small heart.  LHO plays small and Ten, while RHO plays small and then overtakes with the Jack.  So far so good!  She exits with a club!  So, I win with my King and draw the last trump.  Now all I need is the diamond finesse.  It works, and diamonds split 3-2, so I can throw my three spades away on dummy's long diamonds and Club Jack.  Making Six.

P.S.  This story is a bit of a fabrication.  In fact, I didn't play it as above.  I didn't cash the Heart Ace first; rather I just played out a small heart at trick two.  LHO won with his Ten  and cashed the Spade Ace.  If I had played Ace and then a small one, RHO would have been on lead...we'll never know if she had found the spade switch.   [It wasn't clear to the opponents how many keycards we had, since there was clearly confusion in the auction about who was asking and who was telling in terms of number of aces.]