“Onus” (*1/2 out of four) was an endless horror story about a young boy who wakes up in the middle of the woods chained next to an older man and tries to peace together the events of the past day and how they both got there and how they need to escape. If you’ve been longing to see a cross between “Memento” and the original “Saw”, then this is the movie for you; otherwise, this is unpleasant, uninvolving, and (after a while) boring. Good performances are film’s only real virtue.