This two-part t.v. film is a double-helping of disaster movie schlock. As befits an Irwin Allen production, it offers a mixture of stars, melodrama and mayhem. The script is absurdly contrived and, since a t.v. budget doesn't allow for major special effects, it is crammed to the gills with cheap melodrama to distract the viewer from its lack of spectacle. However, these elements actually work in its favor, making it a t.v.-size schlock epic. Georg Fenady's direction tends toward the pedestrian, particularly during the few big setpieces, but his work is solid enough to keep things moving forward. The real attraction here is the performances. Sam Groom makes a solid leading man but it's the supporting cast that really carries the day here: Bert Convy is amusingly smarmy as the spoiled rich man's son/secret drunk, Patty Duke tears into her role as a bitter wife with relish and Cameron Mitchell blusters his way through his role as a corrupt industialist with campy flair. Hanging By A Thread is mainly of interest to schlock devotees but they'll find plenty of campy amusements to enjoy in its jumbo-size running time.