Sam presents a theory to Dean regarding their current investigation in the new "Supernatural" clip. Sam believes that a Greek mythology creature named Siren is behind the haunting in a small town in Iowa they visit, where three men have inexplicably beaten their wives to death.
Siren in fact is a half-bird and half-woman creature with wings who acts as a seductress. Her power is "siren song" which is a kind of appeal that is hard to resist but that, if heeded, will lead to a bad result. The guys realize that behind the murders is a Siren who eventually puts Sam and Dean under their spell and pits the two brothers against each other in a fight to the death.
"Sex and Violence" will air February 5.