At tea time in the Mops-haus, things unexpectedly turned into a discussion about why a dog needs good upbringing. Right in the middle of the argument in the dining room, strange mouse-like creatures suddenly appeared. Uninvited guests began to rob the house. The pug, Josie, called the Mouse King, asked him to recall his subjects, and learned: they were attacked by liars. They feed on someone else’s hate, anger, and greed; they always show up where people are scandalizing and gossiping. And how now can you drive those nasty creatures away? And on top of that, Capitolina and Zephyrka disappeared without a trace. Josie, Muffy, and Cookie set off for the city of liars to save the sisters. Residents of the Mops-haus will have to overcome many difficulties before they understand: the one who seems like a traitor may turn out to be a hero. And if someone did something good for you, tell everyone about it; if you yourself did a kind deed, don’t tell anyone about it.