He knows when the enemy will come. Does he know for whom?
A character takes a warning seriously but protects against the wrong danger. Make the mistaken assumption shape the precautions.
Let two people leave the same encounter with different information without concealing something the viewpoint plainly saw.
After Twenty Years: After Twenty Years, the cigar match, second encounter and illuminated shop window.
Bob waits in a dark doorway for an old friend. A patrolman stops to question him; later another man arrives claiming the expected reunion.
A match lights Bob’s face during the first encounter. Jimmy recognizes him, but Bob does not recognize Jimmy. Later, bright shop lighting lets Bob see that the second man’s nose does not match his friend’s; the note explains the first encounter.
Do not confuse the first patrolman with the later arresting officer. The reveal depends on two separate encounters and a plausible delay.
After Twenty Years, the cigar match, second encounter and illuminated shop window. ↗
Selected passages: After Twenty Years, the cigar match, second encounter and illuminated shop window.
A brief light can reveal an identifying detail to one person while leaving the other without a clear view. The informed person can then act during a delay the other considers ordinary. A later, better-lit encounter lets the remaining person test their assumption. Track who is physically present at each meeting.
Sketch two encounters in order. For each, write who attends, what light or angle lets them see, and the detail they recognize. Give the better-informed person an action between the meetings. Make the second recognition depend on a visible difference already meaningful to the viewpoint.
Use in my storyA character takes a warning seriously but protects against the wrong danger. Make the mistaken assumption shape the precautions.
Introduce a capable character with missing memories by showing what they can do before asking what they know about themselves.
Build a mystery around sincere witness statements whose ordinary wording leaves out something crucial.