4 ideas
Tempest Raj, a stage illusionist whose Las Vegas career ended after an on-stage accident, returns to Hidden Creek, California, and her family's Secret Staircase Construction business, which builds hidden passages and secret rooms into clients' homes. She solves it by treating the sealed room as a trick with a working method rather than a mystery beyond explanation.
An illusionist faced with an impossible result doesn't ask whether it could have happened. She asks how she would have staged it to look this way. That question turns 'no one could have entered' into a search for sightlines, timing, and physical mechanisms. It also treats the apparent impossibility as evidence that someone deliberately designed a false appearance.
An honest locked-room puzzle puts every clue needed for the solution in plain view. It fools the audience by steering where they look and what they think matters, not by withholding facts. Misdirection works on attention, so the reveal feels inevitable in hindsight rather than arbitrary.
A family curse or a hint of the uncanny acts as misdirection at the level of the whole story. It offers an explanation that makes people stop looking for a mechanism. When an impossible event seems to confirm the legend, the legend becomes camouflage for a mundane physical method and a human motive. The investigator's job is to refuse the magical account and treat it as one more layer of the trick.