Guest Stars Ok Ye Rin as Cha Joon Hee Kim Gun Woo as Cha Joon Soo Kang Ki Young as Kim Sang Ryul Sung Joo as Ra Do Woo Kim Yeo Jin as Shim Eun Ha Jung Si Ah as Bong Sun Mi Uhm Hyo Sup as Shim Woo Chul Oh Han Kyul as Sang Ryul's Son Kim Dan Woo as Han Yoo Ra Shin Soo Jung as Min Joon's Mother Jo Sun Mook as Yang Seung Hak Park Ji Hyun as Clara Choi Kim Min Soo as Lee Chul Seung Hwang Ji Ah as Jo Seo Yun Lee Joo Won as Jo Seung Hyun Lee Ja Ryung as MicroBioMed Doctor