The Prisoner of Karlsten's Fortress

Count de Faber is working on a new type of explosive, but finds out that Professor Plussman has beat him to it. After an unsuccessful attempt to acquire the formula from Plussman, he breaks into the professor's house, steals the formula, and kidnaps his daughter, Mary. He takes her to Carlsten Fortress.

• Georg af KlerckerDirector
• Georg af KlerckerWriter
• Willy GrebstWriter

• Nils Olaf ChrisanderGreve de Faber - Sprängämnesexpert
• Maja CasselMary Plussman
• Manne GöthsonC.J. Plussman - Professor
• Arvid HammarlundDoctor Johnson
• Gustaf BengtssonDe Fabers medhjälpare i båten / Medhjälpare på Karlstens fästning
• Victor ArfvidsonBerger - Fästningsförvaltare
• Lilly CronwinUng dam som ringer polisen
• Frans Oskar ÖbergDe Fabers utländska kompanjon
• Anna LöfströmÄldre dam som ringer polisen
• Siri LundinProfessor Plussmans tjänsteflicka
• William EngeströmFiskaren
• Hugo Björnestudent