Philippe Tłokiński as Stan Ulam

Esther Garrel as Francoise

Sam Keeley as Jack Calkin

Joel Basman as Edward Teller

Fabian Kocięcki as John von Neumann

Ryan Gage as Robert Oppenheimer

Sabin Tambrea as Klaus Fuchs

Mateusz Więcławek as Adam Ulam

James Sobol Kelly as Norris Bradbury

Alberto Ruano as Carlos

Richard Mason as George Dyson

Camille Moutawakil as Mici Teller

Sally Cowdin as Irene

Anne-Catrin Märzke as Jacky

Philipp Christopher as Henry Hitchens

Lucy Bromilow as Molly

Martin Müller as Mathematician at Los Alamos

Sonia Epstein as Stefania Ulam

Finbar Lynch as G.D. Birkhof

Karolina Romuk-Wodoracka as Stefania Ulam