In search of an answer to that seemingly simple question, Carl, a curious child, sets off on a great voyage of discovery. As one question is answered, more appear. Soon enough, where once stood but a curious boy, a great scientist will rise.
| Actor | Role |
|---|---|
| IIzzy StannardChild Carl (voice) | Child Carl (voice) |
| DDomagoj ČulinaChild Carl | Child Carl |
| OOzren MuićSamuel Sagan | Samuel Sagan |
| LLado SkorinMr. Schechter | Mr. Schechter |
| VVedran ButoracSnoony | Snoony |
| IIvica GunjačaTeacher | Teacher |
| LLeonarda ObradovićRachel Sagan | Rachel Sagan |
| VVišnja SkorinLibrarian | Librarian |
 Tony SalernoYoung Carl (voice) | Young Carl (voice) |
| LLuka ŠataraYoung Carl | Young Carl |
| KKen Spassione Jr.Carl Sagan (voice) | Carl Sagan (voice) |
| AAnthony SalernoNot listed | Not listed |