DL 2570 then K4 538 at O'Hare
Boston → Chicago → Seoul
Timetable, Chicago time
09:35DL 2570 from Boston at the gate
01:45K4 538 to Seoul leaves the gate
16 h 10 apart on the timetable, overnight
K4 538 leaves 16 h 10 after DL 2570 arrives on the timetable: more than half a day, so not a connection we count.