A pulp hero known as The Apparition has been killing the city’s gangsters. Why?

Criminals beware the night. The Apparition is stalking you. No matter where you might hide, you will be found and you will no longer be a threat to anyone. You will be dead.

But who is The Apparition? Why is this nighttime hooded figure killing the city's criminals? The police suspect Bryan Sloane, a wealthy young man about town, who in a fist fight killed Nick Putty Stryker. Putty was head gangsters David Stryker's only son. So maybe Bryan Sloane disguised as The Apparition is killing David Stryker's mob before they come after him. But is he really The Apparition?