Oli and Vera are twins in the third grade and live happily with their parents and their two small dogs, Lussie and Dandy. For homework, they are asked to craft an imaginary model town. Thrilled by this task, they plan a town in which dogs and children rule - a City of Dogs. Then something unexpected happens. The children and the dogs suddenly find themselves in the City of Dogs. Awaiting them are exciting adventures and new friends, but also important missions, for the City of Dogs is threatened by an imminent danger and the children are destined to avert this threat.