Frank and Joe Hardy finish up a case helping a fellow ATAC (American Teens Against Crime) agent, who sharp-eyed fans may recognise despite her alias! Things seem to quiet down when ATAC sends Frank and Joe undercover to investigate a new Mall opening in Bayport, due to several suspicious accidents there. But things get exciting when the night before the big opening, Joe, Frank, and seven other are mysteriously locked in the mall with a murderer on the loose! If that wasn't enough, everything that could go horribly wrong in a mall, does! A bow and arrow used to kill in the sporting goods store! A runaway elevator! A damsel in distress in the dress shop! Fire in the food court! And much, much more!