Snapper arrives at the JLA headquarters to deliver some mail. While the League receives countless letters every day, these letters are special as they were sent to the League almost two years ago. Looking through the letters, the heroes find that one is a desperate plea for help from a scientist named Andrew Zagarian. Upon investigating, the League discovers that Zagarian has unintentionally created a giant monster he calls The Shaggy Man. Zagarian explains that he was trying to find a medical substitute for lost human tissue, and created a substance known as plastalloy. Unfortunately, an error occurred during the experiment and the artificial body he was working on grew into a hulking, hairy giant. The beast was capable of regenerating from any injury and attacked anything that moved, but Zagarian was able to trap it in a cave. As soon as the doctor’s story is finished, his creation breaks out of the cave and battles the heroes. However, the Shaggy Man’s hideous strength and regenerative powers prove more than a match for the League members. Elsewhere, the other members of the League are busy dealing with the subject of another letter. A massive alien creature is rampaging through South America, draining the Earth of all its natural resources. Eerily similar to the Shaggy Man, Justice League soon find that this monster is also impervious to harm. While the Shaggy Man can regrow body parts anew, this creature is capable of piecing its original body parts back together. After numerous failed attempts to stop both monsters, it seems as though the League has finally met their match. Thankfully, the Flash comes up with the idea of having Zagarian create a second Shaggy Man and sealing all three monsters in a deep pit. The three immortal, indestructible monsters will now be locked in an endless battle, fighting each other for all eternity. The day saved once again; the League returns to Headquarters to tell their friends of their experience.