It started in the distant, rough and tumble Griffin mining town of Shady Sands, infamous for being a town where just saying the wrong greeting could start a fight and not a day went by where a building didn't get wrecked by some wild brawl in the saloon.

Then the Sheriff came to town and started a revolution that swept across the Griffin Kingdoms.

Now, Twilight Sparkle is facing a strangely worthy test of her intellect and skill as a scholar as the Sheriff's strange weapons are now being considered for usage by the Royal Guard for law enforcement duties and Princess Celestia wants her faithful student to answer one rather difficult question.

How can simple foam darts fly truer than any arrow or spell, penetrate magical shields and armour, knock an adult pony out cold, level buildings and yet not leave a bruise on a foal?

The journey to find out the answer will be long, painful, and full of foam.

Set somewhere in Season Six. Definitely after Five.