The Secret of the Missing Diamond | KS2/KS3 Printable Mystery & Detective Game
A ready-to-print mystery game for ages 10–13 (Upper KS2/KS3), combining problem solving, reading, deduction and logic in a fun detective challenge.
A priceless diamond known as the Star of Midnight has vanished aboard the luxurious King’s Wing train — and there are only six possible suspects!
In The Secret of the Missing Diamond, pupils become detectives and work their way through a series of clues and evidence to discover who stole the diamond, how they did it and, finally, where it has been hidden.
Players will examine suspect profiles and statements, track movements using a train map, decipher hidden messages, analyse interview notes, reconstruct a crime-scene photograph, crack a safe combination and match physical evidence before making their final accusation.
Once they think the case is solved, there’s one last challenge: can they recover the missing diamond?
The activity encourages pupils to use reading comprehension, logical reasoning, observation, sequencing, problem solving and deduction, while also encouraging discussion and teamwork when played in groups.
What’s included
The downloadable 23-page PDF contains:
Full Host Guide
King’s Wing train map
Six illustrated Suspect Fact Files
Background information and timeline
7 detective clues and puzzles
Suspect counters and hands-on cut-out activities
Evidence and witness statements
Make Your Accusation sheet
Full case solution and explanation
Final challenge
Case Closed ending
Host answer guide
Easy to use
Designed to require very little preparation. Simply print the game and provide pupils with scissors and pens or pencils. Any cutting required is incorporated into the children’s Detective’s Tasks, so there is no need to prepare all of the puzzle pieces beforehand.
Each clue includes clear instructions explaining what pupils need to do, while the separate host section provides the answers.
The train map and previous evidence should be kept available throughout the investigation, as pupils will need to refer back to information they have already discovered to solve later clues.
Ideal for
Upper KS2 and KS3 pupils, particularly ages 10–13. Great for:
End-of-term activities
Enrichment sessions
Problem-solving lessons
English/literacy activities
Form/tutor time
After-school clubs
Wet play or rainy days
Home education
Family activity days
The mystery involves the theft of a diamond rather than a murder, making it a fun detective-style activity without a violent crime theme.
Format: PDF
Pages: 23
Recommended age: 10–13
Preparation: Minimal — print and play
Additional equipment: Scissors and pens/pencils


