A group of children from 1930s Prague follow the news about the polar expedition of the Chelyuskin, whose members find themselves stranded on a floating crust after the shipwreck. The rescue operation they had planned eventually turns out to be an aid to the striking workers of Děčín...

A medium-length educational color film. Láďa, Honzík, and Karel wander around town, feeling a little bored. Then they meet an older man who offers them an adventure: flying back in time in a rocket. The boys gladly accept and climb into the time machine with little Zuzanka...