From CBS' official press release:

Melinda's secret identity is compromised when Sam catches her in several lies, on Ghost Whisperer, Friday, February 13.

Sam is having second thoughts about his relationship with Melinda when he catches her in several lies, on Ghost Whisperer, Friday, Februar 13 (8:00-9:00pm, ET/PT) on the CBS Television Network.

Ghost Whisperer stars Jennifer Love Hewitt, David Conrad, Camryn Manheim, Jamie Kennedy, and Christoph Sanders.


Source: CBS
(Image courtesy of CBS)