1What a fight actually needs
A germ wears a face — and only one key fits it
You only need two ideas. Watch each one:
A germ wears a "face"
Every germ has a special shape on its outside — like a wanted-poster face. To beat it, your body needs a defender shaped to grab exactly that face.
Only one key fits
Your defenders are like keys, and each key fits just one face. Your body holds millions of different keys — but only ONE matches any given germ.
2Two ways the fight can start
Hunt for the key vs grab it off the shelf
When a germ invades, your body needs the one matching key. There are two very different ways that can go:
Hunt from scratch
The body tries key after key, hunting for the one that fits — while the germ keeps multiplying.
Grab it off the shelf
It already found the matching key once and kept a stack ready — so it grabs it the instant the germ shows up.
3Your turn — be the body, find the key
Tap keys to hunt for the one that fits
A germ just invaded. Tap keys on the ring to test them one at a time — only one matches its face. But hurry: every wrong tap, the germ multiplies.
4Now race two bodies
Same germ, two bodies — one had a practice run 💉
Hunting one key at a time was slow, wasn't it? Here's the big test. The practice run just shows a body a harmless copy of the germ's face ahead of time. Then the real germ attacks both bodies at once. Guess first — then start the race.
Guess before you start the race
Same germ attacks two bodies. One had a harmless practice run before; one never did. Will they both fight it off equally fast?