Roger Quain, escorting two zoo-bound black panthers on the train from Milan to Paris, is unaware that a Western agent, Catherine Ullven, has hidden a microfilm in the collar of one of the animals. But when the train is derailed in the Swiss Alps and the panthers escape, she is forced to involve him in her mission, which now includes enemy agents hunting the microfilm, the animals, Catherine and Roger.

Howard Duff
as Steve Quain

Märta Torén
as Catherine Ullven

Philip Friend
as Chris Denson

Robert Douglas
as Stephen Paradou

Philip Dorn
as Paul Kopel

Walter Slezak
as Doctor Stahl

Kurt Kreuger
as Captain Heimer

Aram Katcher
as Georg

Ivan Triesault
as Assassin

Jay Barney
as Assassin
CinemaSerf
A top secret microfilm is smuggled via a cigarette and a meatball (don't ask!) into the collar of one of a pair of black panthers being transported by "Quain" (Howard Duff) from Europe to the United States. When their train is derailed and the panthers escape, "Quain" and his newly found journalist ...