UA 3913 then UA 753 at Houston
Denver → Houston → Grand Cayman
Timetable, Houston time
21:22UA 3913 from Denver at the gate
12:04UA 753 to Grand Cayman leaves the gate
14 h 42 apart on the timetable, overnight
UA 753 leaves 14 h 42 after UA 3913 arrives on the timetable: more than half a day, so not a connection we count.