Follow the footsteps of one of the greatest musical mysteries of Czech history. A recording of a staged radio report, about the discovery of a promising band that did not manage to become famous, introduces the audience to the environment of the Ostrava underground of the 1960s. The actors of the Vosto5 theater and the frontman of the music group Midi lidi, Petr Marek, discover long-lost sound recordings of the period as well as many revelations about contemporary musicians whose fates were unexpectedly connected to the musical comet called "PROTON".