Silent Hoof, the most deadly assassin in all of Equestria, has taken the place of one of them ponies in Ponyville. His targets are the mane 6. However, Unknown to the assassin, the EBI (Equestrian Bureau of Investigation) has picked up on his trail and sent their top agent, Jim Green, undercover into Ponyville. His mission now is to look for clues and other evidence that would reveal the identity of SH, while protecting both the pony gang and his true identity.