#5: The Santa Rosa Ladies

Midway through the session, sitting west, you arrive at a table of two charming and seemingly capable young women, who promptly bid to the slam.

You lead the ♥8.  Dummy plays low, and declarer takes partner's nine with the ace.  The three of spades goes to the six, ten, and five.  Declarer now cashes dummy's club king and tries a club to the ten, which you win.

What is your next play, and why?