Shes shim, shes sham were the shim sham sisters

She's Shim, she's Sham. We're the world-famous Shim Sham sisters. Shim and Sham in:

The Murder of Equestria

Two sisters, Shim and Sham. They are on they're way to solve a crime.

A stallion asked for some cider before falling dead with three lines along is back.

666, the three bad numbers.

But.... do they hold more than the bad magic, do they hold the key to solve the crime,

or...

will they end up killing them?