"What night-rule now about this haunted grove?" Oberon asks Puck (III ii 5), and Puck replies by telling him that Titania "with a monster is in love." In A Midsummer Night's Dream, nighttime is a time of magic and of confusion. When loves have been sorted out and quarrels resolves, the new day dawns, bringing Theseus to the woods. With him comes reason. The contrast between night and day is one of a series of antithetical relationships in the play.
Oberon speaks of the night-rule in III ii 5.
In III ii 379 Puck worries that the night will be over soon, and they must make hast, but Oberon withholds that "we are spirits of another sort" (III ii 388), not bound by the darkness.