Waking up in the morning and discovering that you are living the days in reverse order is a more serious thing than Groundhog Day! Sixth-grader Gleb Yelizarov just scratched the date "05/23/2013" on an ancient wall - and went with a couple of classmates, first on May 22, and then on the 21st, 20th, 19th... Gleb, who recently transferred to a new school, an excellent student Yura Karasev and Lena Zyuzina, who was mired in household chores, see in the repetition of yesterday's and the day before yesterday's events has some advantages. You can rewrite the final test, avoid a fight with a bully, or even spend all your pocket money on a treat without remorse - because in the morning the bills and coins will be in your wallet again!But the further away the students are from May 23, the weaker the hope of going back to the future - and how to erase the inscription, which you will do only in a week? An excursion to an archaeological find allegedly belonging to the Maya civilization became the beginning of an adventure for the three children, the story of which will not convince any adult. Or is there someone who will believe them?