The fourth episode of "Perfect Crown" aired on MBC on April 18, 2026. It had an intense climax in which Byun Woo-seok's character, Grand Prince Yi An, heroically saves IU's character Sung Hee-ju from a runaway car. This dramatic moment drew in viewers and set a new record for the series' highest viewership ratings.
As cited by The Chosun Daily, Nielsen Korea data noted that the episode recorded a 11.3% rating in the Seoul metropolitan area and 11.1% nationwide. Notably, it achieved 5.3% among viewers aged 20 to 54—a key demographic reflecting changing media consumption habits—ranking first among all Saturday programs. The peak minute rating jumped to 13.8%, showing that the show is getting more popular.
In the episode, Grand Prince Yi An and Sung Hee-ju stage a romantic encounter to keep the paparazzi busy, and they successfully release a photo of their kiss as planned. A meeting at the palace between the king and prince takes place regarding the response from the people.
The grand prince, Yi An, announces that he is ready to recognize their relationship and even marry her. The prime minister, Min Jeong-woo, agrees with him because it is essential not to cause any chaos.
The prince accepts the couple's relationship officially. In contrast, the queen dowager, Yoon Yi-rang, and other relatives scheme to split them apart before the crowd becomes more interested. On the other hand, Hee-ju tries to strengthen their relationship by going to the baseball stadium game together with the prince.
Although they do not dress in the same uniform, the picture appears on the stadium's Kiss Cam, which catches many people's attention. As the relationship progresses, Yi An becomes more conscious of Hee-ju's presence and support despite all external factors.
According to Daum, following a kissing scene, he manages to control himself from anger after hearing her say, "I am on your side," meaning that she is becoming more emotional. Court Lady Choi Jin-sook trains Sung Hee-ju in royal etiquette to prepare her for her role as the Grand Prince's wife. She also spends time with King Yi Yun during his visit.
The episode's climax is when Sung Hee-ju drives with King Yi Yun and the car's brakes fail. Despite efforts by her and Prime Minister Min Jeong-woo to stop the vehicle, it speeds uncontrollably until another car blocks the way. Relief comes as Grand Prince Yi An appears to stop the car and save her.
The fifth episode is scheduled for Friday, April 24, at 9:50 p.m. on MBC.
