Circumnavigator and South Seas voyager Luden Dassow (Erwin Geschonneck) returns with his white fishing boat Tambari to his home village Koselin. But the other fishermen are hardly welcoming. Only the son of the chairman of the cooperative, Jan Töller (Frank Reichelt), is interested in his exciting and adventurous seafarer stories.

After Dassow’s death, the cooperative gets Dassow’s beloved boat, but lets it decay. Eventually, Jan takes over the boat and turns it seagoing again with the help of wagoner Kaßbaum (Kurt Böwe) and several children. When the fishermen suffer a financial emergency, they want to sell the Tambari, even though that would violate Dassow’s last wish.

Based on a children's book by Benno Pludra.