In Truth Or Dare, a bunch of college kids go to Mexico and come back with something awful, contagious, and beyond the reach of Pepto-Bismol, or broad-spectrum antibiotics.
It's a curse, creating a fatal vector that moves from person to person, placing Truth or Dare in the same general category as Final Destination or The Ring, though in this case the internal logic of the movie is complex, confusing, and as a result the movie is not very much fun.
And though most of the characters exist only to be killed, they are generic and disposable even by the standards of cut-rate horror movies. Good girl Olivia (Lucy Hale) wants to spend spring break working for Habitat for Humanity, but her hard-partying roommate and friend Markie (Violett Beane) lures her south of the border, with a bunch of other undergrads.
In Mexico, a guy at a bar lures them to an old mission, where they are affixed with the curse that follows them back to the States and forces them to play endless rounds of truth or dare.
If you try to opt out, you die. If you play, you might be asked to kill someone else, prompting participants to ponder (theoretically) whether they will submit to the kill-or-be-killed ethos of the situation.
Suffice it to say, there is a lot of killing, and the students prove vulnerable to the pull of ruthless self-interest. This could be wicked, gruesome fun, but there isn't much of that in Truth or Dare, which gets lost in the needlessly knotty and constantly shifting rules of the curse.
Midway through the game, for instance, the students discover they no longer have the option of telling the truth to pass the curse along. So it's suddenly dares only. Markie, for instance, is dared to smash Olivia's hand with a hammer. An hour of this is like getting your own hand smashed with a hammer, although perhaps if you are smashed, or hammered, or on spring break, it plays better.
Survivors end up returning to Mexico to investigate the origins of the curse in order to find a way to disrupt it, or to free themselves from its grip, leading to a finale of truths, dares, and demonic detours.