The couples YoonTaem and SunSun have been dating for one year,it's their anniversary. So, their friends decide to throw a party for  their special day. Sunny and Taemin decided to give their lovers a special present but their anniversary presents aren't so sweet. Taemin and Sunny soon find out that Yoona and SungMin have been dating each other for 2 years. Heartbroken, Sunny and Taemin become vow never to fall in love again. But,they soon get closer and fall in love with each other.