Question

Which literary technique involves something unexpected that engages the reader to move toward discovering that key to the entire work?

situational irony
peripeteia
sense of an ending
conceal and disclose

Answer 1

Peripeteia seems to be the answer from what i can gather from my Brit lit class.

Answer 2

The literary technique used for what the question asks is peripeteia.

It´s a turning point, a change that made the action goes to its opposite, according to Aristotle it is one of the most effective techniques in drama and tragedy.

When the peripeteia happens is the moment when the plot starts to move steadily to its conclusion. In the tragedy is the moment where the hero´s fortune change from good to bad.

I hope this answer helps you.