ABC has released three sneak previews for tonight's episode of Agents Of S.H.I.E.L.D., which is called "The Only Light In The Darkness." In the first clip, the agents face Patton Oswalt and the lie detector. In the second clip, Skye finds out that Agent Ward is not a good man. In the third clip, Blackout demonstrates his power when a man refuses to give him a ride to Portland. In "The Only Light In The Darkness" episode, with their world turned upside down, Coulson races to save the life of his one true love as the mystery of "The Cellist," which began in Marvel's The Avengers, is finally revealed on Marvel's Agents of S.H.I.E.L.D. Marvel's Agents of S.H.I.E.L.D. stars Clark Gregg as Agent Phil Coulson, Ming-Na Wen as Agent Melinda May, Brett Dalton as Agent Grant Ward, Chloe Bennet as Skye, Iain De Caestecker as Agent Leo Fitz and Elizabeth Henstridge as Agent Jemma Simmons. Guest starring are Bill Paxton as Agent John Garrett, Patrick Brennan as Marcus Daniels, Amy Acker as Audrey, B.J. Britt as Agent Antoine Triplett, and Patton Oswalt as Agent Koenig. "The Only Light In The Darkness" episode was written by Monica Owusu-Breen and directed by Vincent Misiano. Marvel's Agents of S.H.I.E.L.D. airs on Tuesday, April 22, 2014 at 9 PM ET on ABC.