You were suffering. Your mother was lying in a hospital bed in a serious condition and you had to save her, but you couldn't.

"I can help you, with a contract."

you heard someone's voice and turned around, it was Go Won. He looked like an angel, but that wouldn't be the case...

"I will save your mother on one condition, as soon as you sign the contract, your soul will be mine and in 10 years you will die."