Jiwan and Heewoo are two wealthy, good-looking twenty-six-year-olds from elite Korean families. Despite their perfect appearances, each carries a fatal flaw. Jiwan lives recklessly, addicted to luxury and excess, while Heewoo drifts through life numb and uninterested in anything around him. When Jiwan’s father suddenly cuts off his credit cards, his lavish world collapses overnight. Desperate to afford a limited-edition coat he refuses to give up, Jiwan turns to a supposedly easy, high-paying side job at a secretive private club and convinces his childhood friend Heewoo to join him. Expecting nothing more than pouring drinks and entertaining guests, Jiwan instead finds himself pulled into situations far beyond his control, while Heewoo, long bored with life, begins to awaken to a dangerous new thrill.

Ten years ago, on an unusually cold winter day, Do-eon’s father brought home a young boy. Given the name Mi-yi, the child became Do-eon’s younger brother in name, though they shared no blood. At eighteen, Do-eon begins to care for Mi-yi out of simple compassion, gradually becoming his sole protector and the only safe place in his world. Sheltered behind Do-eon’s quiet devotion, Mi-yi grows up clinging to him as his one constant. Seven years later, everything changes when Mi-yi is involved in a shocking incident that leaves their father at the bottom of a staircase. Haunted by guilt and secrets he cannot yet reveal, Mi-yi asks only one thing of Do-eon: not to hate him when the truth finally comes out. A story of protection that turns into dependence, The One and Only explores how love, guilt, and obsession blur when someone becomes the only person you have left.