Kuroda Mika (Yamashita Rio) is engaged to Sakurai Toru (Furukawa Yuki), a guy who works at a trading company and is a great catch. She earns the resentment of females at work for foisting troublesome tasks on her colleagues because she is about to get married. Part-timer Asai Mitsutoshi (Miyachika Kaito) is a nice young man who helps Mika with her work without making a face when he sees her. One day, Mika receives a message from a weird account. With that as a start, inexplicable events begin to occur around her. Mika receives a direct message on social media as if her movements are under surveillance. Then she gets a phone call at her workplace from someone claiming to be Toru's former fiancee Hirose Kanata (Fukagawa Mai). The mounting harassment gradually takes a toll on Mika's mental state. Meanwhile, an incident causes Toru to suddenly get close to Hinata (Hagiwara Minori) and they end up having a relationship. But this is just the prelude of Hinata's horrifying revenge plan. The true faces and relationships of the mysterious characters are slowly revealed. Who will have the last laugh? The TV drama is based on Tachibana Azusa's manga Risky ~ Fukushuu wa Tsumi no Aji ~