The mysterious apocalyptic sect "The All-Seeing Eye of God" takes hostages at the exhibition "The Soul of the Renaissance" in the Stroganov Museum. By chance, among the visitors is Sergey Razumovsky, previously known as the avenger in a mask by the nickname "Plague Doctor". The police forces are preparing to surround the museum, and by pure coincidence, not far from the scene is Major Igor Grom, who recently returned to the authorities and once caught Razumovsky…
But is there not too much coincidence in this story? Someone clearly planned the attack of the "Eye" and a new meeting of former sworn enemies, but for what purpose? And what connection does this have with the long-missing psychiatrist Benjamin Rubinstein and his patients? The grand plot "Your Brother in Darkness", tightly intertwined with different series of the BUBBLE universe, puts a final point in the cult confrontation between Grom and Razumovsky and opens a new chapter in the history of the dark side of St. Petersburg…
