I'm sorry if I misunderstood you but I get the impression that you feel like a One Time Pad is trivial to break?

Just because you can construct any plaintext of that size and a suitable key to generate that ciphertext doesn't mean you've broken it or know anything about its content (aside from the maximum length of the plaintext).

The answer is supposed to be a keyword, I seriously doubt it's an OTP they are asking for...