To Haddon it seemed as if the plank slid backward under his feet. His dive was purely instinctive but it was a fine one, wide and shallow, that carried him well out. As he shot to the surface he almost collided with Ted Hinckley, but he was quite unconscious of the other’s nearness. Out of that numbed daze of horror and dismay but one thought, one motive, rose to dominate him. He must reach Cavanaugh before the shark.