American Ninja 4: The Annihilation (1990) CIA agent Sean Davidson and his sidekick Carl are sent into the stronghold of sadistic British ex-soldier Mulgrew to rescue some Delta Force commandoes who have been captured and tortured. When Sean, Carl and pretty doctor Sarah run into some problems, Peace Corps vet Joe Armstrong is lured out of retirement to stop Mulgrew's plan to explode a nuclear device in New York City.