Synopsis: The crime bosses of Metropolis meet on the ocean to discuss a method of getting rid of Superman for good. Suddenly, a volcanic eruption under the surface of the water forces an island to the surface. The criminals name the island "Island X" and decide to only invite other criminals who aren't yet wanted by the police or Superman. They argue over who will become King of Island X and decide that the best way is to give each of them a chance to kill Superman. They construct a giant "punchboard" with 50 random murder methods for each of the 50 criminals. Each criminal choosed a method and whoever succeeds in killing him will become King of Island X. However, Superman is flying overhead and hears their plan with his super-hearing. He decides he's going to help them to try and kill him. He flies back to his Metropolis apartment to retrieve a ring. The next day, at a weight-lifting exhibition, a criminal named Heist Nelson tries to kill Superman with diamond tipped drills. The drills break on contact with his skin, but Superman lets Nelson go back to the island. Another criminal, Nitro, tries to kill Superman with lightening. On a stormy night, he writes a letter to Clark Kent at the Daily Planet saying that he's placed a bomb on the highest building in Metropolis so that Superman will fly up to deactivate it. Superman is struck by lightening and isn't harmed. The criminals of Island X each go through failed attempts to kill Superman until only two of them remain. The 49th criminal draws "vibrations" as a method, so he kidnaps Lois Lane to draw Superman out to the island. When Superman gets there, he is forced to wear a small tuning fork around his neck while the criminal strikes a giant one with a hammer. Again, Superman is unscathed. Before Superman can take Lois and leave, the last criminal goes to the punchboard. The chosen method is "Superman must die of a broken heart." He decides the best way to achieve this is to kill Lois. The criminals all fire their guns at Lois, but Superman tosses her into the air and out of the line of fire. He then punches all of the criminals into individual holes on the punchboard. Superman tells them they're all under arrest for the attempted murder of Superman. One of the criminals reminds him that the island is in international waters so they're outside the jurisdiction of U.S. law.
Superman responds by picking up the island and flying it to the middle of Lake Erie. He then reveals that the ring he put on earlier in the story is actually a tiny camera, which he has used to record all of their attempts on his life and get enough evidence to jail them all at once. The story ends with Lois wondering aloud to Clark if a broken heart really might be Superman's weakness.