Albert Einstein: Time Mason (Albert Einstein: Time Mason #4)

Left for dead in the old west, Albert Einstein has to get the train back on the tracks if he wants to stop a thief from destroying our timestream. And the only way to do that is to hijack a train with legendary Young Gun, Billy the Kid! But as Einstein closes in on the villain, his secret identity is threatening to be exposed back at Princeton. Saddle up for this epic adventure!