The film features Oleg Yefremov as the good Aibolit and Rolan Bykov as the evil Barmalei.

First, they seize Aybolit’s ship at sea, throwing him, Avva, and Chichi overboard along with their medicines.

The bandits untie Aybolit, demanding he hand over all his medicines so they can be immune to illness forever.

In the finale, Barmaley orders his henchmen to gather all the local pirates by the riverbank, where they tie Aybolit and his companions to an old boat.

The Tragedians and Comedians from Mosfilm intervene, battling the pirates and rescuing Aybolit, Chichi, and Avva.