While Jang Yeong Shil has advanced to another level of engineering a time telling device, Jang Hee Jae is still trying to build his own water clock based on what he knew from the trip to Ming China. Princess Sohyun is helping him with it all along, making her a rare female carpenter and mathematician of her time.
The royal Uncle and his daughter of Ming China came with a decree from the Ming Emperor, allowing Joseon to develop their own almanac. They were upset to see Jang Yeong Shil missing from the welcoming group of Joseon ministers, and couldn’t believe that he had died. Lee Chun managed to track down Jang Yeong Shil and brought royal Uncle to see him. It was a happy reunion, and royal Uncle surprised Jang Yeong Shil with thoughts that are far too advanced for those times (“perhaps a time will come where there is no need for a King,” says royal Uncle).
Jang Yeong Shil explains how he broke out of the unhealthy circle of wallowing in angst and survivor’s guilt, when one day while he was wandering around and sleeping under a persimmon tree wasting away, a persimmon dropped onto his face and unexpectedly set him thinking again. It made him curious again about the workings of nature and he can see the stars in the sky again. That’s how he ended up in Namyang, teaching the village children songs to remember the seasons and the constellations, making an easy to read sundial, and refining the sound-making stones.
That’s also how he ended up creating an automated clock which used no water but instead many ball bearings and simple mechanisms. He explained how the clock works to the mathematician who’s helping Jang Hee Jae, and followed Jang Yeong Shil to his workshop out of curiosity. He is marvelled at Jang Yeong Shil’s ingenuity, removing the use of water when every other time telling devices used the water flow rate to tell time. Jang Yeong Shil tells him to tell Jang Hee Jae where the workshop is, as he believes that Jang Hee Jae’s curiosity will win over his jealousy.
It’s an internal battle for Jang Hee Jae, as he struggles with the return of Jang Yeong Shil, whom at the first official meeting with King Sejong, declares that the water clock that Jang Hee Jae is working on cannot be made an official clock. Not only that, he was also beaten up by his crazy friends and some other yangbans, who were mad that Jang Hee Jae did not kill Jang Yeong Shil back then, which allowed him to return and make a fool of them. Jang Hee Jae finds the workshop and stares with disbelief how simple Jang Yeong Shil’s mechanisms were to make a fully automated and accurate clock without the use of water.