In this second book of the Thunder Rose Collection Moxie, Diego, Pamela, Amber, and Edgar are back to solve new and mysterious goings on at the ranch.

The Black Stallion has shown up again and it's not what everyone thinks. Atwood or El Diablo as he used to be called was infamously known for his string of bad luck upon whoever owned him. With no one willing to care for the aging stallion he spent his final days at Thunder Rose under Pamela's care. During his stay, the ranch had one bad incident after another until the day that El Diablo transitioned.

Now ten years later, sightings of El Diablo by the horses and hands at the ranch lead Moxie and the rest of the group on a dangerous passage into the heart of the beast.