Possi Must Be Saved. Sissi has returned to Possenhofen. There she has to learn that Arkas has lured her family into a trap. With a promissory note signed by her mother Ludovika, he can finally claim Duke Max's property for himself. But Arkas reckoned without the citizens of the area. While the Count casts the anchor off Possenhofen in his newly acquired steamboat, the missing money is collected in a hurry. Sissi is not idle either. An inventor cruising the lake in his submarine gave her an idea of how to evict the Count from the family property.