In a land of two kingdoms - one ruthless under King Vladan’s conquests, the other hidden behind a magical lake and ruled by kindly King Dobromil - Queen of Fire enchants Princess Mariana in living flame to force Dobromil’s hand in ceding the kingdom’s fabled Ruby Heart. Desperate, Dobromil uses a magic ring to summon the ever-jovial Tadeáš from Vladan’s realm; Tadeáš braves the flames, rescues Mariana, and wins her heart, only for their triumph to be threatened once more.