The idiom "smell a rat" means to discover or suspect something fishy or wrong about a situation or person. It is often used when someone has found out that someone else has been dishonest or deceitful.

The idiom "when hell freezes over" is used to describe a situation that is highly unlikely to occur. It is often used as an expression of disbelief or skepticism when someone makes a statement that seems unrealistic.

The idiom "bundle of nerves" is used to describe someone who is very tense, anxious or nervous. It's a figurative expression that compares a person's emotional state to a bundle of twigs that are tightly tied together and are easily agitated or upset.

The idiom "page-turner" refers to a book, movie, or other form of media that is highly engaging and keeps the audience's attention, often causing them to eagerly turn the pages or keep watching. It suggests something that is exciting, suspenseful, or simply hard to put down.

The idiom "blood on hands" refers to a situation where someone is responsible for a crime or a wrongdoing that has caused harm or damage to others. It implies that the person has committed an act of violence or aggression that has left physical evidence in the form of blood stains.