NCIS: Los Angeles' Callen will have more enemies that he can count during "Spiral."

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Working undercover in a mail room to collect intel on an arms dealer, Callen (Chris O'Donnell) will quickly find himself fending off his target, but their tense encounter will be interrupted by a swarm of terrorists (see sneak peek video below).

Callen will be taken hostage with the rest of a considerably massive office building, and it will be up to Sam (LL Cool J), Kensi (Daniela Ruah), and Deeks (Eric Christian Olsen) to save the day. Unfortunately, the episode's baddies will be two steps ahead of our heroes - the entire skyscraper will be wired to blow.

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Cue helicopters, dangerous escapades out sixteenth story windows, and some good old-fashioned elevator shaft climbing.

Penned by Dave Kalstein ("The Frozen Lake," "Three Hearts") and directed by Larry Teng ("Deep Trouble," "Unwritten Rule"), the midseason premiere is sure to provide plenty of pulse pounding action.

"[Larry Teng] is at the helm. [Dave Kalestein] is architectural master," tweeted executive producer John Peter Kousakis. "This ep. is going to blow you away #NCISLA."

Find out more when NCIS: LA returns to CBS on Jan. 5 at 10 p.m. ET.

Tags: NCIS: LA NCIS: Los Angeles television CBS