A Christmas codebreaker escape room for KS3 Computer Science: a 50-minute lesson with a PowerPoint, five puzzle cards, a team answer grid and solutions.

An escape room is a team challenge: pupils solve a chain of puzzles against the clock, and each answer unlocks the next step. In this one, a prankster called The Glitch has locked the school’s festive server. Teams crack five locks, each a short computing task, and one letter from each lock code makes the master password.

The five puzzles

• Lock 1: decode a Caesar cipher (the shift is given in binary).
• Lock 2: convert binary bytes to ASCII letters.
• Lock 3: work out five logic gate circuits (AND, OR, NOT) and read the bulbs as a binary number.
• Lock 4: colour a pixel bitmap to reveal a hidden word.
• Lock 5: trace a short Python program with a trace table.

How to use it in class

Allow 5 minutes for the story and rules, 35 for the puzzles and 10 for the reveal and debrief. Teams of 3 or 4 share one set of cards and one answer grid. Hand out each card when a team shows a correct code, or give all five at once. The deck has a click-to-start 35-minute countdown with a buzzer, two hints per lock and a final-lock reveal. No computers needed.

Included

• PowerPoint (15 slides, 16:9) with click animations and optional sounds
• Puzzle cards and mission briefing (PDF, A4, colour and ink-saving)
• Team answer grid (PDF)
• Teacher solutions with full working, hints and timings (PDF)

All puzzles are original. The photos and sounds come from Wikimedia Commons (CC0, public domain, CC BY or CC BY-SA) and are credited in the slides.

Last updated: November 2026