The inveterate mama's boy Dusya couldn't understand why such a cool girl like Ksyusha suddenly needed him? She dragged him to her mansion, bought him fashionable rags, taught him shooting and fighting techniques. Is he being trained as a personal security guard? But which of Dusya - a couch potato, a glutton and a mattress - is the guard?.. There can only be two answers here: either something bad is being planned against him, or Dusya is ahead of Mendelssohn's march and marriage to the beautiful Ksyusha who is madly in love with him! And what, Dusya decides, there are not such miracles in the world. But it turns out that there is a third option - absolutely incredible. To find out the truth, a brave mama's boy investigates two strange murders...