10 parts Ongoing Kim Mingyu's life is built around love, loss, and responsibility. At just 26, he's a single father to his four-year-old son, Hansol, after losing his wife during childbirth. Between his demanding job as an architect and raising a child on his own, Mingyu barely has time to breathe, let alone take care of himself. But he keeps going-for Hansol, for the memory of the woman he loved, and for the quiet promise he made the day she passed: "I'll give him everything."
When work becomes too much and his parents begin pressing him about moving on, Mingyu knows something has to change. At the recommendation of his best friend, Seungcheol, he hires Jeon Wonwoo, a soft-spoken barista with a gentle smile and calm eyes, to help look after Hansol.
Wonwoo expects nothing more than a simple babysitting job. But what he finds instead is a small family still grieving, still healing, and still learning how to love again. Hansol latches onto Wonwoo almost immediately-calling him "Mumma Woo" and drawing crayon pictures of the three of them like it's always been that way.
Wonwoo doesn't want to get attached, but the warmth of the home, the sound of Hansol's laughter, and the quiet way Mingyu smiles when no one's looking make it impossible not to.
Everything becomes more complicated when Mingyu, out of desperation, tells his visiting parents that he has a new lover-hoping to stop their constant pressure to move on. But now they want to meet the supposed boyfriend, and with no one else to turn to, Mingyu asks Wonwoo to help him one last time:
"Just pretend... just for a week."
Wonwoo agrees, for Hansol's sake. For Mingyu's sake. Maybe even for his own.
But fake smiles start to feel real. Late-night conversations blur the line between pretending and longing. And the way Mingyu looks at Wonwoo when Hansol falls asleep in his arms makes it harder and harder to remember what they're not.