It's Firestorm versus an undead foe who's getting into the ethereal mix with Martin and trying to take over control. The Phantom Stranger is on hand to help out. Jean-Marc and Randy Lofficier guest write this issue, which feels a lot more supernatural than it turns out to be. The only real supernatural elements–besides a ghost haunting Firestorm–are the strange settings where the possessed Firestorm ends up fighting the Phantom Stranger.
The writing, which is fine and does have more character development than the civilian halves of Firestorm usually get (and by more, I mean a scene as opposed to no scenes), is nothing compared to Alan Kupperberg's art. Kupperberg is rather cartoony and it brings a real energy to the comic. It's a strange story and a straightforward art style wouldn't get the job done.
So Kupperberg's the essential here.
It's silly and long, but not a bad comic.
Ghosts!; writers, Jean-Marc Lofficier and Randy Lofficier; artist, Alan Kupperberg; colorist, Nansi Hoolahan; letterer, Bob Lappan; editors, Janice Race and Gerry Conway; publisher, DC Comics.