After Lucifer got defeated by the warrior's of Heaven during his plotted invasion of the world, the powerful demon punished by God Almighty and let him astray on Earth powerless, poor, helpless and without a memory that he's a former fallen angel and demon. He's now unfortunately living in a human body of a weak girl as Kim TaeYeon, she avoided everyone and let herself be alone by just working as a barista living on her daily boring routine. She's naive and sometimes dumb yet her lady boss Tiffany Hwang treated her as a normal person and found her cute, the 34 years old widowed woman has a huge fondness on her since she started working at Sweet Heaven's Delight. How will their relationship grows if TaeYeon prefers to be boring and alone while Tiffany needs more of her company?