Marta's surprise birthday party sets in motion a spiral of tragic events.

An old pickpocket named "Cardinal", during the days of the International Festival of Youth and Students, decides to gather old “personnels” to prepare small and large thefts from the festival participants. During the "conference" it turns out that a complete "personnel crisis" has come. The ensuing meeting with the former bootlegger — Senka-Moroz, who broke with his past and found happiness in his family and honest work, leads the Cardinal to confusion and mental confusion. A conversation with Professor Muromtsev, a terminally ill person who nevertheless cares about the fate of others, shock the "Cardinal" and he takes the first but decisive step towards a new life, breaking with the criminal world.

Milo and Kida reunite with their friends to investigate strange occurances around the world that seem to have links to the secrets of Atlantis.