On October 19, while traveling to Jeju Island to celebrate their anniversary, Chaeyoung was in a Plane crash. Along with Nayeon, Jihyo, Jeongyeon, Tzuyu, Sana, Momo, Dahyun, and Mina, she became stranded in the woods. Chaeyoung seemed to have escaped with only minor injuries at first, though after the death of Mina, she became unresponsive. Sana examined her chest to find major bruising. Sana realized that she had a cardiac tamponade, fluid surrounding her heart. Sana used a tube from a bottle that Nayeon and Jihyo found to drain the fluid. Sana, Nayeon, and Jihyo could get Chaeyoung to the front of the Plane where Tzuyu and Dahyun were. Chaeyoung was airlifted to Asan Medical Center, then sedated and moved to Seoul National University Hospital, where Momo and Sana work. After that day, she fell into a coma. After thirty days, they turned the life support machines off, and her friends sat with her while she died. To confuse matters more– Chaeyoung signs a 30-day DNR order where if she hasn't fully recovered, they are to discontinue life support.