Mikhail is a former aircraft designer, and now just a grandfather who constantly gets into ridiculous situations. One day on December 31, she and her grandson Seryozha sheltered a dog who was hiding from New Year's fireworks. The dog was given the name Stepka. Soon after his grandson was taken away by his parents, Mikhail becomes ill. And now Stepka has very little time to call for help and save his master's life. But it is very difficult to do this, because none of the people knows the dog language. The only way out is to find Seryozha, who, as it seems to Stepka, understands him. And then the four-legged hero goes to the other side of the city to meet incredible adventures.