I was thinking that it could be in the sense of something catchy or something that attracts attention. For example, a tabloid headline like "I slept with a Martian!" can be referred to as a "hook" to get people to buy the paper and read the story. It originates from fishing (in the sense of something used to grab/reel in a fish).

I am certainly no expert on this. But, is hook some kind of drugs?

Can you give the phrase in context?