'Agents of S.H.I.E.L.D.': What are Bobbi Morse and Mack really after?

ABC

Warning: This story contains major spoilers from Tuesday's episode of Marvel's Agents of S.H.I.E.L.D. Read at your own risk.

Are there more Hydra traitors in S.H.I.E.L.D.'s midst?

During Tuesday's midseason return of Marvel's Agents of S.H.I.E.L.D., viewers finally learned part of the secret Bobbi Morse (Adrianne Palicki) and Mack (Henry Simmons) have been keeping from Coulson (Clark Gregg) and his team: They're searching for Nick Fury's toolbox. Does that mean they're actually working for Hydra?

"It's not wrong to assume it," executive producer Jed Whedon says. "We've all been burned by Hydra before. We're a little shell-shocked."

But Palicki insists it might not be so black and white. "They do have a secret, but whatever they're doing, they think is the right thing," the actress says. "It's not necessarily malicious, but you have to keep an open mind." Interjects co-star Nick Blood: "Hitler thought he was doing the right thing." "Good point," Palicki replies.

Whatever their intentions may be, Simmons says, "This secret that they have is gonna have quite an impact on the team." That will be particularly true when it comes to Bobbi and Hunter (Blood), who have just started to rekindle their relationship. But Bobbi lied point-blank to Hunter during Tuesday's episode, explaining that the secret they've been keeping is that they're members of a support group. "He knows her too well to believe anything she says, really," Blood says. "He's always on guard, always suspicious. With most people, and probably particularly with her, he's been let down too many times in the past to take it on face value. When you care about someone, you want to believe that they're telling you the truth. He wants to believe her."

Marvel's Agents of S.H.I.E.L.D. airs Tuesdays at 9 p.m. ET on ABC.