 Prof. Maracot claims to have located the deepest trench in the Atlantic and is vehement that he shall go down in the specially prepared submersible (actually a bathysphere) along with Headley and Scanlan.On reaching the edge of the trench, a description of the undersea world is presented.The team comes face to face with a giant crustacean who cuts off their line and hurls them down into the trench.