Framed for Equestria's biggest crime to date, Pinkie Pie now faces the gallows!

In a last-minute effort to save her, her friends requested that Princess Celestia summon the "greatest investigator alive" to seek at least one clue that could prove Pinkie Pie's innocence within a week. To their relief, she agreed. Instead of a pony, however, she brought "Ace", a skilled private investigator from Earth.

A pioneer to a parallel universe, Ace has to mix real-world logic with mythology and magic if he is to find the real "Cupcake Killer" before the next batch is made!