Someone who is having difficulty to find something out, after strugling a lot with no success, needs a fresh pair of eyes to assist them. So to complete the sentence with the appropriate idiom, we can finish with "What it really needs is a fresh pair of eyes" <em>(another person to examine closely in addition to anyone previously.)</em>
“Mystery is when the spectator knows less than the characters in the movie. Suspense is when the spectator knows more than the characters in the movie.” The fact that two terms often considered synonyms have actually two opposite definitions may surprise, but once you go deeper the difference is even enlightening.
