Lee Hae-eun, an angel tasked with becoming a guardian angel to finally become human. However, the child she is assigned to protect is Yeon Do-yun, a young man who is not only perfect in every way, but seemingly blessed by the gods. Having stuck by his side for some 20 years to help him out with anything, their bond—which has lasted all the way through college—is about to reach its final chapter with her last mission. "Find the human's destined soulmate!"