Under the Badgers Rock (1978)

The gamekeeper Straka lives by himself in the Bohemian forest hill. He has quarreled with his only son. He cannot come to terms with the fact that his son has abandoned his beloved forests and settled in a town. He has never even met his grandson Vasek. Following an illness, however, little Vasek needs some country air, and so one day his mother Jarmila delivers him to her father-in-law's cottage. At first Straka is angry, but Vasek is an unaffected lad and throws himself with verve into all the little adventures that the forest provides.

Unfortunately the movie Under the Badgers Rock is not yet available on HBO Max.