De Robins en het Robot Komplot plot
The Robins are two sisters and are on holiday together. They drive through nature and suddenly they see a car in the ravine. There's another man in there. They quickly go there and drag the man out of the car, just before the car explodes. The man is in bad shape and can just make it clear that the girls have to keep a letter for him. No one should know about it and if he didn't survive, they should read the letter. The man dies and the girls decide to read the letter at home. On the way home they are chased by two men who want the letter, but the Robins don't just hand them over. The letter turns out to be about a gunshot, which the man is said to have discovered. The weapons are in the Devil's Cave. The sisters decide to go to the police, but they tell them that the man has escaped from an asylum and that it is therefore a false alarm. However, the girls are not feeling well. Then why were those guys chasing them? They decide to take a look at the Devil's Cave themselves.