Seo Ji-seong is a programmer on the A.I. Developent Team at Smart Home Appliances. While working on a refrigerator, she accidentally inserts a chip belonging to the National Intelligence Service. Instead of a program that will rate the freshness of vegetables, it will root out the undesirables from a dating pool, potentially saving people heartache. Seo Ji-seong herself wants to fall in love, but with the right man. Despair sets in when her program determines that her oh-so-perfect fiancé, Jeong-han, is not her Prince Charming after all ! Jung Kook Hee is a firefighter who spends little time on social media, leaving Seo Ji Sung with little data to analyze. She meets firefigher Gook-hee, who has no social media presence. This leaves Ji-seong without a shred of data for her program to analyze. She can't help but be skeptical, not knowing a thing about Gook-hee 's past. Should Ji-seong take a leap of faith with him, even if it could mean another hearbreak for her?