The main characters are teenagers studying at the same school—only separated by one hundred years. Kolia Gerasimov lives in Moscow in 2024. One day, together with his friend Fima, he discovers a mysterious artifact in their physics teacher’s office — the cosmeon. This strange object transports him a century forward, into the year 2124. In this future, humanity has already made contact with alien civilizations and joined the Cosmic Federation. There Kolia meets Alisa Selezneva, a girl who also studies at the same Moscow school but in another era. She assists her father, Professor Seleznev, a renowned space zoologist, while quietly mourning her mother, who disappeared in a battle with villains.
