The Flash has traveled to outer space with Green Lantern and battled pirates high in the skies above the city. But now a murderer is stalking the city's streets with a connection to a string of serial killings leading centuries back to the founding of the Gem Cities--and perhaps to the murder of Barry's own mother. It will take all of the Flash's power, all of Barry's detective work, and a little help from the spectral superhero Deadman to take the killer down--because there are some horrors even the Flash can't outrun.