Agents of SHIELD's Melinda May's past as the Cavalry will come to light in season 2.

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The taciturn martial arts master has a dark history, but May (Ming-Na Wen) isn't about to tell her tale to just anyone. Coulson (Clark Gregg) doled out a piece of her story last year, and executive producer Jed Whedon promises viewers will learn more as season 2 progresses.

"She's gone through something crazy in Bahrain that we've hinted at and we will explore in this season," Whedon said, according to Entertainment Weekly.

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As season 2 commenced filming, however, Wen was still in the dark as to why May originally swapped fieldwork for the role of desk jockey.

"I wish I could say I [knew] but I'm not lying, I have no idea. Absolutely none," Wen told Blu-Ray. "And I've giving up asking our writers because they're like S.H.I.E.L.D., you don't get an answer.

Find out what really happened in Bahrain when Agents of SHIELD returns to ABC on Sept. 23 at 9 p.m. ET. Click the video below to see a teaser for season 2.

Tags: Marvel's Agents of S.H.I.E.L.D. television ABC Marvel