Moriarity takes over as the sympathetic father activist personified by John P. Ryan in the first two films. He plays a former actor and father of one of the monster babies born during the events in Parts 1 and 2. The film opens with a trial, during which prosecutors argue that Moriarity's caged monster infant should be executed. Moriarity successfully argues that the child should be sent to a place where it can't harm anyone.
Only five of the monster babies are now left in America, and experts claim no others will be born. So the judge decides to send the creatures to an isolated government island where no human can harm them, and where they can't harm any human. Four years later, after Moriarity has written a book about his experience and failed to reconcile with his ex-wife (Black), he's invited to visit the island by a team of scientific experts determined to learn what the babies are now like. As it turns out, the former babies are now fully grown, just as bald and mutated, and 10 times deadlier than they were as infants.
"Island of the Alive" has a faster pace than "It Lives Again," plus we get a much better view of the monster babies, thanks to the wonderful effect of stop-motion animation. But it's definitely inferior to the first two "Alive" films. The full-grown creatures definitely look ridiculous. And Bernard Herrmann's original music -- which greatly enhanced the first two movies -- isn't present here, aside from the opening credits. Moriarity does a pretty good job with the role, playing it straight, despite the film's ultra-campy subject matter. (He also starred in the far superior Cohen film "The Stuff.")
Like the other "Alive" films, this one delves into the subjects of abortion, birth control and the rights of the deformed -- but not quite as effectively as the first two films. By the second half of the movie, the killer babies are all grown up. Truth is, the real novelty of Parts 1 and 2 is that they were about babies. This film ultimately focuses on run-of-the-mill, mature mutants in rubber suits, which even perform the ultimate cliché climax of attacking punk rockers at an amusement park.. The best parts of the movie are at the beginning, when the mutants are still infants. The choice sequence features a group of game hunters who show up on the island, looking to kill some monster baby. Naturally, they wind up as the creatures' meal.