Unable to sleep, marketing team assistant manager Lee Yu-joo kept messing up project after project. He happened to meet sales team member Yoo Hae-sung at a drinking party and spent the night with him, sleeping so soundly that hhe was late for work in the morning... Realizing it was due to Hae-sung's soft chest, Yu-joo began using Hae-sung as a remedy for her insomnia... “Yoo Hae-sung, be my pillow.”