Three schoolchildren accidentally find a magical portal in the Holy Trinity St. Sergius Lavra and are carried away into the past. Now their goal is to return home, and for this they need to go through the wonderful forest of the XIV century during the Tatar-Mongol yoke and the Battle of Kulikovo. St. Sergius of Radonezh will help the teenagers.
The story begins with the good, but poor Potter, who once finds Flint, a magical artifact that makes its owner rich, but instead sends a death curse. Potter can be saved only by the dedication of the main character - a girl named Twinkle. Without hesitation, she rushes to the rescue of a friend, helping him to understand that love and honest work are more important than money and power.