SAN DIEGO -- Fans expecting to see a snippet of the new "Marvel's Agents of S.H.I.E.L.D." television show got a surprise at Comic-Con - the chance to see the entire debut episode.

Thousands of fans went wild when Marvel executive Jeph Loeb surprised them with the episode, which features Clark Gregg as Agent Coulson, the S.H.I.E.L.D. agent everyone thought died in Marvel's recent blockbuster film "The Avengers."

The show follows Coulson as he builds a team of fellow agents to deal with the growing problem created by superheroes and their foes.

Fast-paced and full of comic moments, the episode laid the groundwork for the series. Until Friday, little had been revealed about the ABC series set to debut Sept. 24.