Mark Sheppard guest stars on the April 29 episode of Supernatural.

The actor plays Crowley, a demon that tells Sam and Dean he can help them locate the remaining Horsemen rings so they can trap Lucifer and prevent the Apocalypse. 

This plan won't exactly go swimmingly, however. Check out a clip below from "The Devil You Know" and visit our Supernatural spoilers section for a complete look ahead at the series.

[video url="http://www.tvfanatic.com/videos/the-devil-you-know-clip/" title="The Devil You Know Clip"] [/video]

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.