In one sunny city live two cute and unusual children: boy Petya and girl Toma. Toma is an "ice queen" because she never smiles and often cries, and Petya is a coward who lacks courage. One day Petya's mom and Toma's dad decide to turn to the doctor. The doctor is unusual, he has candies against fear, and with the help of other sweets he can heal from anger and cunning, stupidity, sadness, lies, gossip.
But, by an incredible coincidence, a suitcase of yellow color with miracle drugs comes into the wrong hands. Under threat are the lives of Toma's grandmother, the pilot Verevkin - Toma's father, the tamer of tigers Bulankin.
Toma's grandmother, doctor, Toma and Petya set off on a quest for the suitcase containing the magic medicines.