You are North, the declarer in 6♦. East leads the ♥K.
Do you have a 'lock'?
Scroll down for the full hand, a solution/suggestion and/or explanation
The Entire Deal
You have a lock. Win the ♥A. Draw trump. Play the ♣AK. Ruff a 3rd round club. Cross in diamonds. Ruff the 4th round in clubs. Surrender the ♥J. East is endplayed.