Zajatci Ďáblova chřtánu (2006)

A story about time travel and friendship unfolds during a summer. Siblings Klára and David discover a frightened boy near their parents’ cottage. Unable to find anyone else to help, they take care of the unusual child, Artur, and try to find where he came from. Simultaneously, a peculiar man named Robert appears at a nearby veterinary clinic, offering gold coins for food. Separately, the characters discover clues pointing them towards the home of a local eccentric, Kobza, and then to a cave called Devil's Mouth. Could this cave be a portal to another world and time? And will Artur and Robert find their way back home through it?