Hulu's sci-fi anthology series Dimension 404 is rounding out its cast.

Will & Grace alum Megan Mullally and Fresh Off the Boat's Constance Wu have boarded the six-episode drama from YouTuber Freddie Wong. The pair join an ensemble that also includes Sarah Hyland, Joel McHale, Lea Michele, Robert Buckley, Patton Oswalt, Ashley Rickards, Sterling Beaumon and Ryan Lee.

In a standalone episode, Mullally will play Director Stevens, a hardened, no-nonsense military commander who oversees a top-secret, cutting-edge NSA project tasked to fight terrorism. Wu will portray Jane, a military psychologist on active duty who wants nothing more than to spend Christmas leave with her wife and daughter. However, the U.S. government cancels her plans and reassigns her to a much more vital task: helping the NSA's unusual but most valued agent overcome his performance issues in order to stop a deadly terrorist attack.

Distributed by Lionsgate, the anthology series draws inspiration from the internet’s notorious "404" error code and aims to evoke the feeling of wandering onto the weird side of the web at 3 a.m., stumbling upon stories that cannot be explained in the world as we know it. Among the sorts of questions explored in the series: What if an obscure cartoon held the secret to time travel? What if energy drinks caused the apocalypse? What if the NSA’s top analyst was a gigantic, all-knowing cube of sentient meat named Bob?

Dimension 404 is created by Dez Dolly and Will Campos, with co-creators Dan Johnson and David Welch. Executive producers include Arnold, Dolly, who also will serve as showrunner, and Wong, who will direct.