Bae Joohyun, The beautiful heiress of Bae family's fashion company. Everyone loves her because of her intelligence and her hardworking face, but despite of that,she has a cold personality because of her past. She then crosses paths again with Kim Taehyung her ex which she hated so much, a spoiled brat and a trouble maker who lives next door and is also dependent of his parents'money which also owns a big company. Both of them lived in the same big apartment for years without the knowledge that both of them are living closely. What if she meets him? who was caught cheating, who was the reason why she became cold, and was the one who broke her heart Plagiarism is a crime ?