The Agents of SHIELD will give Simmons up for dead before the season 3 premiere even begins. Everyone except Fitz, that is.

'Agents Of SHIELD' Season 3: Kree Stone Is Off Limits [PHOTO], Fitz Teases Search For Simmons

Simmons' (Elizabeth Henstridge) untimely disappearance will be several months in the rearview by time the fall opener rolls around, and with no leads to go on, Coulson's (Clarke Gregg) team will have no choice but to presume their biochem genius is never coming back. Fitz (Iain DeCaestecker), however, will continue to burn the midnight oil as he moves heaven and earth to find out what really happened to his wonder twin (see video below).

"It's Fitz's mission to get Simmons back. It's a solo mission," Henstridge revealed to Zap2It. "What happened was so crazy and there was no trace of her, that what do you do? She disappeared into this rock that goes to liquid sometimes, but we don't know why and we don't know when. I think that the whole team has tried and nothing has worked, so at some point you have to go, 'She's gone, we have to move on.' But Fitz refuses to do that."

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Good on you Fitz.

It appears the distraught scientist's hard work will quickly pay off for viewers, if not for the character himself.

"It's not something that will be strung out too long," Henstridge teased.

Dive into the mystery of the Kree rock when Agents of SHIELD returns to ABC this fall.