This documentary details the life of Klaus Fuchs who was a spy for the Soviet Union while working on nuclear research in the United States and Great Britain. It also discusses the contributions of German scientists to the atomic bomb.
| Actor | Role |
|---|---|
| HHeinz-Dieter KnaupNarrator (voice) | Narrator (voice) |
 Klaus FuchsSelf - Interviewee | Self - Interviewee |
 Carl Friedrich von WeizsäckerSelf - Interviewee | Self - Interviewee |
 Otto HaxelSelf - Interviewee | Self - Interviewee |
 Nevill MottSelf - Interviewee | Self - Interviewee |
 Jürgen KuczynskiSelf - Interviewee | Self - Interviewee |
 Joseph RotblatSelf - Interviewee | Self - Interviewee |
 Wolf Graf von BaudissinSelf - Interviewee | Self - Interviewee |
 Robert JungkSelf - Interviewee | Self - Interviewee |
| GGrete KeilsonSelf - Interviewee | Self - Interviewee |
| KKarl WirtzSelf - Interviewee | Self - Interviewee |
| GGünter FlachSelf - Interviewee | Self - Interviewee |
| RRuth WernerSelf - Interviewee | Self - Interviewee |
| WWolfgang MeyerSelf - Interviewee | Self - Interviewee |
| MManfred von ArdenneSelf - Interviewee | Self - Interviewee |
| RRudolf PeierlsSelf - Interviewee | Self - Interviewee |
| FFritz BernhardSelf - Interviewee | Self - Interviewee |
| CChristel HolzerSelf - Interviewee | Self - Interviewee |
| GGeorgy FlyorovSelf - Interviewee | Self - Interviewee |