Plant every clue where a sharp reader could find it

A classic mystery is a puzzle the reader is invited to solve. In 1929 Ronald Knox set out ten rules for detective fiction, among them that the criminal must be mentioned in the early part of the story, and that the detective is bound to declare any clues he discovers. Modern mysteries break Knox's rules freely, but the principle under them has held: at the reveal, a reader who goes back should find the answer was on the page.

That leaves you two timelines to keep straight: what actually happened, in order, and the order in which the reader finds it out. Red herrings have to be plausible, not merely loud, and the real clue has to appear before the reveal, ideally hidden among other details the reader has no reason to weigh.

A mystery looks backward: who did this, and how? A thriller looks forward: will the protagonist stop what is coming? The thriller reader often knows more about the threat than the hero does, and the pleasure is suspense rather than deduction, carried by rising stakes, a clock, and chapters that end on a turn. Plenty of books blend the two. Knowing which question leads tells you what each chapter owes the reader.

1. Before chapter one, write the real sequence of the murder night under Timeline in Story Hub, one lane for the murderer and one for the detective: who arrived when, the poisoned tea, the switched cups. Add each suspect under Characters with motive, opportunity and the lie they tell.
2. Keep a clue list in Free Notes: each clue, the chapter where the reader first sees it, and the red herring placed beside it.
3. As you draft, ask Robin: "Where does the reader first see the chipped cup?" or "Which chapters mention the vicar's alibi?" Robin searches your chapters and answers in chat. If a clue only turns up after the reveal, you find out before a reader does.
4. Invite two beta readers with Can comment access and ask them to leave a note at the end of each chapter naming their suspect. Notes arrive grouped by chapter, so you can see when readers get close, and whether the reveal lands as both surprising and fair.
5. Run Reader Pulse (Premium) on the middle chapters and read the Closing hook and Tension estimates, where a sagging middle tends to show first. It is a preview before your first readers, not a verdict.
6. Before you rework the solution, choose Save Version Manually. If the new ending doesn't hold up, compare the two versions and restore the earlier one.

• There is no dedicated clue tracker or suspect board. Free Notes and Characters in Story Hub carry that, in whatever format you like.
• It does not find plot holes by itself. Robin answers questions about what your pages say; deciding whether the solution is fair is your job, and your readers'.
• Reader Pulse estimates engagement from the text. It cannot tell you whether the killer is guessable. Only people can.