A suddenly interrupted call and the subsequent disappearance of a journalist friend lead Larisa to an apartment rented by a friend in St. Petersburg. In a letter with delayed dispatch, Svetlana writes to Larisa that she sees Masonic symbols everywhere. It was about the Freemasons that she was going to write when she arrived in St. Petersburg. Everything would be fine, but Larisa soon also begins to see Masonic signs everywhere, and something strange is happening in the rented apartment... Is she really next? And how is the famous Rotunda on Gorokhovaya, filled with secrets and terrible legends, connected with the disappearance, where the friend was at the time of her disappearance? According to one legend, the hatch on the floor of the Rotunda is the gate to the underworld...