Since Chicago Journal science editor Cliff Nolan never filed his story on Dr. Pavo Zarnik's claim to have discovered a tenth planet out beyond Pluto, investigative reporter Mark Manning is ordered to cobble together an article. Quite a story, if true--only Mark, fresh from his discovery of Cliff's dead body, is convinced the story's bogus and Zarnik's an impostor. (The clues that give Zarnik away, in fact, occasion the cleverest bit of detection here.) Weighted down by the assistant he's been assigned, adoring cub reporter David Bosch--who knows that Mark is gay and indicates that he'd come out of the closet to spend the night with him--Mark, determined to be faithful to his loftmate, architect Neil Waite, goes in search of the story, and promptly runs into a gigantic conspiracy that links Chicago's impending millennial blowout, Celebration 2000, to the gay-baiting Christian Family Crusade, the Pentagon, and somebody with very deep pockets indeed. En route to the movielike final conflagration, which reduces the lead villain to ""hissing meat,"" Mark will have time for an elaborate party--evidently a trademark of this series (Flight Dreams, 1997)--and some torrid coupling, in his dreams and out. The conspiracy is the stuff of standard paranoia, and Mr. Hissing Meat's identity pretty obvious. But the scenes of gay domestic life, which show a welcome sensitivity, could go far toward helping this gay mystery enlarge, or even escape, its niche.