From the show:

Eve and Evan are twins roped into yet another desperately dull Halloween by their parents. Managing to break free, they maraud, pumpkin-smash and toilet-paper, inadvertently crossing the thin line between worlds on this night of all nights. They enter a house and meet a demoness who has been lying in wait for just such a pair. A harrowing cat-and-mouse game ensues with the stakes being nothing less than their immortal souls. All Hallows Eve is a tale wrapped up in horror, comedy, and blood… and definitely not for young children.