Smell danger by reading the lead

Elizabeth Taylor said, "Success is a great deodorant. It takes away all your past smells."

A bridge expert has an acute sense of smell. He notes an unpleasant aroma wafting across the table when the apparent facts don't add up. He then tries to work out who has been telling fibs. Or, he uses his olfactory organ to smell out the meaning of a lead - as in today's deal.

How should South play in five spades after West leads the diamond two?