The unique boarding school “Waldenstein” is about to be closed due to corrupt speculators. But four children are not willing to accept this: the chaotic adventurer Amalia; the brave Buddhist Jonas; the shy bookworm Tom, and the optimistic sausage-lover Maik want to save their beloved school. Thinking of what to do, they discover an ancient legend of hidden treasure following the trace of famous archaeologist Heinrich Schliemann. A daring journey begins which takes the children along the river Oder to Poland.