The beginning of the school year: in the FZS No. 4 - classes with books and inkpots on their desks; pioneers go to school. They are engaged in mathematics. Leningrad. Plant "Konstruktor": press, stamping machine, samples of designers. Moscow. A circle of young biologists at the zoo: a cage with tigers, a lion cub is weighed; measure the rabbit; the calf is drinking from the bottle; zoo employee feeds baby ferrets and otters.