On a spring morning, neighbors Valentina Kaplan and Oksana Savchenko wake up to an angry red sky. A reactor at the nuclear power plant where their fathers work--Chernobyl--has exploded. Before they know it, the two girls, who've always been enemies, find themselves on a train bound for Leningrad to stay with Valentina's estranged grandmother, Rita Grigorievna. In their new lives in Leningrad, they begin to learn what it means to trust another person.