UA 3851 then AC 592 at Houston
Seoul → Houston → Toronto
Timetable, Houston time
17:54UA 3851 from Seoul at the gate
11:55AC 592 to Toronto leaves the gate
18 h 01 apart on the timetable, overnight
AC 592 leaves 18 h 01 after UA 3851 arrives on the timetable: more than half a day, so not a connection we count.