When things are out of their proper places or not happening the way they should, we say they are amiss. Sherlock Holmes, like many sharp detectives, would quickly notice when something was amiss at a crime scene.
The word amiss can be used as an adverb, as in the sentence, "I spoke amiss." Or you could use it as an adjective, as when you think something is wrong or missing — "Something in the room is amiss." Either way, amiss refers to something that is wrong, off the mark, or "missed." Once in a while, the word amiss can imply that something fishy or foul has taken place. In Hamlet, when Marcellus said, "Something is rotten in the state of Denmark," he might as well have said, "Something in Denmark is amiss."