The search for “Thomas Shaw” continues on Berlin Station.

In EPIX’s spy thriller, newly-appointed CIA officer Daniel Miller (Richard Armitage) finds himself deep in his undercover mission to find the mole within the intelligence agency, known only by the alias of “Thomas Shaw,” who’s been leaking classified intel.

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ET exclusively premieres a first look from Sunday’s episode, in which Daniel is grilled by the CIA’s Berlin station chief Steven Frost (Richard Jenkins) over his growing obsession over the faceless mole.

“In this scene, Frost warns Daniel not to let his personal agenda cloud his judgment. That's a portentous statement, because it could, and perhaps it is, and Daniel doesn't know it. It’s only his actions that will determine that,” Armitage told ET exclusively via email.

“Separating a personal agenda from professional judgment and action will be the mark of this man,” the British star said of his character. “Daniel is ‘in service’ to the CIA. He is a public servant. We'll find out in the next few episodes how that 'service' will function and if his patriotism will trump his personal agenda. (No pun intended.)”

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Armitage, 45, also reflected on working opposite Jenkins, 69, whom he called “wonderful.”

“His level of commitment is so high. You search his eyes and find only ‘Steven Frost.’ Daniel is presenting a face of ease to Frost, one which he knows is a thin veil, which Frost is penetrating,” Armitage said. “As actors, we often feel like this: ‘He sees me, he doesn't believe.’ This scene held all of those things. Daniel presents himself to Frost, and I to Jenkins -- the moment is two characters acting their roles and two actors buried deep in those characters.”

Berlin Station airs Sundays at 9 p.m. ET/PT on EPIX.

Watch the full-length trailer and one of the opening scenes from the premiere below.