In "Heard it Through the Grapevine" Lee Joon and Ko Ah Sung started to suspect Han Jung Ho.
On the 16th episode of SBS Monday/Tuesday "Heard it Through the Grapevine" (script Jung Sung Joo, director Ahn Pan Suk) broadcast on Apr. 14th Han Jung Ho (played by Yoo Joon Sang) and Suh Bom (played by Ko Ah Sung) started to get suspicious about Han Song's secret that Han Jung Ho (played by Yoo Joon Sang) was leading.
On this day, Han In Sang learned that Jang Hyun Soo (played by Jung Yoo Jin) followed the orders of Han Jung Ho and had falsely gotten admitted into a hospital. Before this, Han In Sang had heard from Min Joo Young (played by Jang So Yeon) about the scandals that Han Song Yi had committed in the past and had been in contemplation.
Afterwards, Han In Sang started to discuss this with Suh Bom. He said, "I honestly don't believe this. I lived for twenty years as a son but I can't even say confidently that I know my father." With that, he was in pain.
Suh Bom asked, "Did you ever rebel or anything?" Han In Sang said, "There's no way for this to happen. You see this every day though. You see that they live like a clock" and explained Han Jung Ho's personality.
