In the Europe of the 1800s, Denmark, England, and Russia each have a childless king; all three need an heir to the throne. Speedily arranged marriages, births, and cunning strategies bring King Christian IX, Queen Victoria and Tsar Alexander II to the throne. 30 kings and queens, princes and princesses tell a fantastic story about power, love, triumph, tragedy and honour. Through the frank interviews, viewers are given a unique insight into generations of family unity across country borders. And in this way, a piece of exciting European history is recounted from a time when superpowers, through marriage, controlled Europe.