Any place where a earth pony has touched the ground. Any spot where a unicorn has used magic. Wherever a pegasus has flown through the air. With the help of a newly discovered particle that reveals how magic affects the physical world, Twilight can track the actions of all kinds of ponies. However, an unprecedented wave of crime is starting to sweep across Equestria, and a common link between many of the cases indicates the existence of a dangerous new foe. Someone who can perform impossible feats without using magic at all. Can Twilight's cutting edge science compete against a criminal mastermind who seems to have no limits?