Come to think of it I was wondering how many people know the difference between player knowledge and character knowledge.
Player knowledge is stuff that we the people know. Which basically sumarises almost everything that is going to happen that hasn't. If we are say leading a scene somewhere. Example. Jane slipped Samantha a drug. We the people know it.
Character knowledge is what the character knows. Example Jane slipped Samantha a drug. Jane knows this. Samantha doesn't.
The hardest part is keeping there separate. For character knowledge Samantha can't just yell out you drugged me. Because she doesn't know that Jane did she might taste something funny and suspect it however it wouldn't make sense if she knew it was a drug. Jane can simply lie and if made believable it works.