A blazing meteorite has hit the Florida town that is the central battlefield in the war between humans and aliens. Her name is Hanna Cheek.

In “Sovereign,” the final chapter of Mac Rogers’s rollicking “Honeycomb Trilogy,” the downtown actress Ms. Cheek replaces Becky Byers as Ronnie, the forceful, ruthless human leader, transforming what had been a rigid, steely character in Part 2 (“Blast Radius”) into a seductive force of nature. With a jutting jaw and the swinging limp of a warrior, Ms. Cheek projects commanding power, then mixes in vulnerability, cutting wit and some girlish vamping. It’s the kind of magnetic star turn that could unhinge a production but is actually precisely what this one needs.

As in “Blast Radius,” Mr. Rogers displays an impressive control over his sprawling material, creating a convincing postapocalyptic world inside a sturdy theatrical structure. He is assisted again by the director Jordana Williams, whose emphasis on clarity is exactly what this plot-driven epic demands.