From USA Network's official press release:

Jonathan Silverman guest-stars in "Truer Lies" this Friday at 10/9C.

Shawn and Gus must prove a pathological liar is telling the truth in order to stop an assassination plot.

Psych stars Corbin Bernsen as Henry Spencer, Dule Hill as Burton "Gus" Guster, James Roday as Shawn Spencer, Kirsten Nelson as Karen Vick, Maggie Lawson as Juliet O'Hara and Timothy Omundson as Carlton Lassiter.


Source: USA Network
(Image courtesy of USA Network)