Preston were in complete control of the first half but for all their dominance they could only manage the one goal in an all too easy first 45 minutes for the visitors.
That came after 12 minutes when a low cross from the right by Danny Mayor fizzed across the front of the Exeter backline and Hume came in at the back post to finish off.
Exeter were completely out of sorts and North End goalkeeper Thorsten Stuckmann barely even got his gloves dirty.
However, it was a different story midway through the second half when Elliott Frear laid the ball off to Liam Sercombe and he fired a fine equaliser from the corner of the box.
Preston’s winner came with just six minutes remaining as Exeter’s erratic ‘keeper Artur Krysiak came and failed to take a long goal-kick from Stuckmann, Hume beat him to it and rounded the stopper with ease before slotting home his second of the game to heap more misery on the Grecians.