Another day, another find for dog trainer Cory Pratt’s cadaver dogs Alice and Rex. This time the find is a mass grave with three bodies and a second single grave over three decades old, leading to a cold case that Cory’s sibling and Chicago Police detective Crystal has to solve fast, as the killer of the four men is still out there.

While the identities of the men are determined one by one, the bodies are linked to an infamous crime that remains unsolved to this day. Figuring out what happened all those years ago while trying to minimize the current body count, Cory, Crystal and the dogs are hot on the heels of the killer. But their involvement puts them right on the killer’s list and in more danger than they bargained for.