I. Synopsis
Go Ae-Rin (Jung In-Sun) suddenly loses her husband. A mysterious man, Kim Bon (So Ji-Sub), lives next door. Kim Bon is a legendary NIS agent. 3 years ago, he was involved in a failed secret operation, and the woman he loved died. He has since become disconnected from the world and lives alone quietly. He helps his neighbor Go Ae-Rin uncover a conspiracy, which her husband became involved with.
II. Accolades
| Year | Award | Category | Recipient |
| 2018 | 2018 MBC Drama Awards | Daesang (Grand Prize) | So Ji-sub |
| 2018 | 2018 MBC Drama Awards | Drama of the Year | My Secret Terrius |
| 2018 | 2018 MBC Drama Awards | Writer of the Year | Oh Ji-young |
| 2018 | 2018 MBC Drama Awards | Top Excellence Award, Actor in a Wednesday-Thursday Drama | So Ji-sub |
| 2018 | 2018 MBC Drama Awards | Top Excellence Award, Actress in a Wednesday-Thursday Drama | Jung In-sun |
| 2018 | 2018 MBC Drama Awards | Best Supporting Actor/Actress in a Wednesday-Thursday Drama | Kang Ki-young |
| 2018 | 2018 MBC Drama Awards | Best Child Actor | Kim Gun-woo |
| 2018 | 2018 MBC Drama Awards | Best Child Actress | Ok Ye-rin |
| 2018 | 2018 MBC Drama Awards | Bromance Award | So Ji-sub, Son Ho-jun and Kang Ki-young |
