You are South. As declarer in 6♠, you get a low heart lead from West. How do you play?
First, there is no way to guarantee your contract. If West holds both the ♦K and the ♣A, you’re toast. There is a way to give yourself the best chance, however, if only one of the finesses is working.
Win the ♥K in dummy and draw trumps. Finish cashing your heart winners, pitching two clubs from dummy. Next, re-enter dummy with a trump and play a club to the king. If East rises with the ace, you’re home. If your king loses to West’s ace, ruff the club return in dummy and try the diamond finesse.
This is a 75% slam, so if you go down, don’t feel too bad.