You Want Me, a Detective, to Treat a Disease?

On a dimly lit boat, a cat and a detective are having a discussion. "Tell me what you asked me to do." "Meow, meow, meow." The detective frowned. "Really, why would I want to talk to a cat." The detective was extremely disappointed with his decision. "What are you talking about? I'm just greeting you in cat language." "So that's it, so what's your problem?" "I came to you for treatment." "?, I'm just a detective, not a doctor. You have the wrong person." The cat scoffed. "Of course I found the wrong person, it was you." "Wait a minute, I'm getting more and more confused. What do you mean you're the one you're looking for?" The detective drank the water from his hand. "I don't know how to treat illnesses." "No, you will." "No." "The disease I want to cure is the disease about the world." This time it was the detective's turn to scoff. "What? What's wrong with this cat?" The detective smiled and turned around, he had heard the funniest joke ever. He looked over the side of the ship. He saw...