CZ 3391 then KE 868 at Guangzhou
Zhengzhou → Guangzhou → Seoul
Timetable, Guangzhou time
13:30CZ 3391 from Zhengzhou at the gate
13:20KE 868 to Seoul leaves the gate
23 h 50 apart on the timetable, overnight
KE 868 leaves 23 h 50 after CZ 3391 arrives on the timetable: more than half a day, so not a connection we count.