Agents of SHIELD's Cal Johnson has been playing it cool - if you can believe that - but Skye's father will go off the rails before season's end.

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Dear old Dad isn't known for his even temper. Packed like a powder keg, Cal (Kyle MacLachlan) is poised to go off once more in Agents of SHIELD's two-hour season finale.

"We've seen him have PCP moments of rage strength, but the tales of Cal annihilating a while village and doing other terrible things on a vast scale just don't jibe with the man we know so far," executive producer Jeffery Bell informed TV Guide Magazine. "That will change. We're taking a cue from the comics where Cal - or Cal Zabo, as he's known - is Marvel's Mr. Hyde, as well as a very fractured and broken Dr. Jekyll."

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Titled "SOS" and "SOS: Part 2," the upcoming finale will see the battle between Coulson's (Clark Gregg) SHIELD, Gonzales' (Edward James Olmos) SHIELD, and the Inhumans come to a deadly head. The identity of the soon-to-be-deceased character is currently unknown, and it remains to be seen if Cal's rage will have anything to do with someone's untimely demise.

Find out more when Agents of SHIELD airs Tuesdays at 9 p.m. ET on ABC. Click the video below to see a preview for the series' next episode, "Scars."