Kang Si U

[Work Mode: ON]
He is known as the office's "Three-No-Man" for one simple reason: no smiles, no people, no apologies. Whether a project wraps up successfully or someone makes a mistake so ridiculous it would leave everyone else in stitches, Si U never laughs. He rarely loses his temper either. Even when a subordinate makes a major blunder, he doesn't bark orders or explode like some managers do. Instead, he delivers blunt, concise truths that cut straight to the point and leave people thoroughly shaken. Still, his work speaks for itself. Without flattering his superiors or putting on a fake front for those below him, he continues to rise through the ranks at remarkable speed.

[Work Mode: OFF]
Si U is well aware of his "Three-No-Man" nickname, but it doesn't bother him. In fact, his work mode hardly ever switches off. He arrives at the office first and leaves last. He has no girlfriend, nor does he spend his evenings drinking with friends. Then one weekend, he unexpectedly runs into Ji Yun at a convenience store and bursts out laughing at her ridiculous appearance. A crack begins to form in the routine that had once been as impenetrable as bulletproof glass. And whether by chance or by fate, Ji Yun always seems to be there beside him.

(Source: tvN)