“One day I will return – wait for me. I will return to take back what’s mine.”

When Heather was born, everyone thought she would die due to her weak heart. Upon her mother’s callings, a demon showed up and saved her life by sharing his heart with hers. There was only one condition; she would live until the demon’s powers ran out. Not knowing anything about the mark she had on her chest from the day she remembers herself, she falls in love with the demon, marking the start of a forbidden love…

What happens when she finds out the secrets her aunt and the demon have been keeping deeply hidden from her?