Though he's in the dark about what he's carrying in his black satchel, courier pilot David Randall (Derr) knows it must be something ominous. First the astronomer who hires him to deliver it to Dr. Cole Hendron (Keating) starts muttering about how money soon won't mean anything. Then he's met at the airport by Hendron's daughter, Joyce (Rush), who muses glumly that she hasn't the courage to face the end of the world.
His brow furrowed, Randall tags along as Hendron calmly confirms the data from the satchel. A rogue star, Bellus, will smash into the Earth in mere months. Only a handful of humans might survive, and only if they travel by rocket to Zyra, the mysterious planet orbiting Bellus.
Other astronomers ridicule Hendron's findings, scotching his plan for an international space ark. Undaunted, he turns to private investors, notably gnarled plutocrat Sydney Stanton (Hoyt). Though Stanton insists on taking over, he crumples under Hendron's offer: Your money for your life.
Hendron, Joyce and her fiance Tony Drake (Hanson) assemble a crack team to build and stock the ship. Randall is kept on, but he feels out of place among the specialists, especially since he loves the spoken-for Joyce. His rivalry with Drake leads him to give up his place on the rocket, which is limited to only 43 people; but Drake, realizing that Joyce truly loves Randall, tricks him into staying.
The rocket is completed just in time; Bellus fills the sky as those chosen by lot hurry on board. But in the final moment, the armed, panicky mob long predicted by Stanton materializes, endangering humanity's only chance of surviving the last day of planet Earth.
When rival suitors collide!




