GQ 681 then TK 1848 at Athens
Sofia → Athens → Istanbul
Timetable, Athens time
21:55GQ 681 from Sofia at the gate
13:05TK 1848 to Istanbul leaves the gate
15 h 10 apart on the timetable, overnight
TK 1848 leaves 15 h 10 after GQ 681 arrives on the timetable: more than half a day, so not a connection we count.