What do you get when you combine an empty Ponyville library, government cost cutting on strongbox locks, and a particularly mischievous unicorn? Sweetie Belle with a top-secret list of military tele-spell network addresses.

What do you get when you combine three clever fillies with terrible official password discipline? The Cutie Mark Crusaders with access to the central strategic armaments computer.

What do you get when you combine two-factor activation with a tremendously short-sighted and very arrogant Celestia? Nothing good.

Takes place in the same universe as, and is set immediately after (but isn't "canon" to), Fluttershy: Royal Game Warden (?). You don't need to read that one. You should, because it's a Certified Hood Classic, but you don't have to.

Death and Violence tags are general. No blood and guts, but if you're faint of heart, there's an intentionally squicky sequence that probably hits a lot harder if one has a fear of hypodermic needles, so be aware.