Unexpected plot development (5)
I believe the answer is:
twist
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unexpected plot development</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for twist that I've seen before include "See Oliver" , "Sixties dance; cheat" , "Wrench, distort" , "Writhe" , "another card, please" .)