What is the meaning of this sentence: "What are you trying to pull here?"
Here is the contexts:
Alex: Well, um, I know she loves playing the harp, so I found this beautiful music box that plays one of her favorite songs.
Sheldon: Now, Amy already has a real harp. And it can play any song.
What are you trying to pull here?" (The Big Bang Theory)
P.S.: Thanks for your answers!

Question

What is the meaning of this sentence: "What are you trying to pull here?"
Here is the contexts:
Alex: Well, um, I know she loves playing the harp, so I found this beautiful music box that plays one of her favorite songs.
Sheldon: Now, Amy already has a real harp. And it can play any song.
What are you trying to pull here?" (The Big Bang Theory)
P.S.: Thanks for your answers!

Answer

I might have a hard time explaining this, but: I would say it's the same thing as saying "what are you hiding?" or "what are your true intentions?" to someone who is obviously hiding something.

Answer

What are you trying to get away with?  (You are trying to cheat me?)