An unseen force has been manipulating our world. The only clue they left behind is a strange, bloodstained yellow button. Where did it come from?

Who left it here? The button could easily be the most important object in not just our world, but in every world--which is why the Reverse-Flash will kill to possess it!

Featuring the creative team of writers Joshua Williamson and Tom King alongside top-tier artists Jason Fabok and Howard Porter!

Collects Batman #21-22 and The Flash #21-22.