He admitted to io9 that much of the superhero drama has "a fanciful element to it".
"That's fun," he confessed. "We won't be doing 'ha-ha' comedy, but there will be funny situations."
However, he insisted that the series, which stars David Lyons and Summer Glau, "will be grounded".
"The trick [is] creating a reality for the world of the show, communicating that reality to the audience, and then telling your stories within the boundaries of that reality," he explained. "That's what we're trying to do. In our world, the stakes are real, the consequences are real [and] the stories have danger elements that are real."
Wirth also confirmed that the show will feature "an over-arching story" related to the villainous Peter Fleming (James Frain).
"There will be serialised aspects to the show," he confirmed. "Each week... [the threat will] be someone dispatched by [Fleming], or him, or some other villain."
The Cape launched last night on NBC with a two-hour premiere. The series will move to a regular timeslot on Mondays at 9/8c from January 17.