Alphie Bloom thought his Summer would be boring, until he gets told he has inherited a castle, Hexbridge Castle, which has been closed up for hundreds of years. Alphie receives a letter explaining that he must be sure not to open the basement with the talisman-key enclosed. Alphie and his two cousins have a great time exploring the castle and finding a large bear skin rug that magically comes to life and takes the trio on a magic carpet ride through the city. Unfortunately, they nearly escape the wrath of a two headed dragon before reaching the safety of the castle again.

Alphie attends school where two horribly mean head mistresses have targeted him as a victim. There, the students are preparing to put on a theatrical show in the auditorium until a fire breaks out. In fear the show may not go on, he offers the use of the castle which could allow someone to open the basement and let a nest of hibernating dragons out. While the show is in progress, the two headmistresses turn into the two headed dragon in an attempt to get the talisman-key, but good always wins, and the dragon is taken down. Adventure, magic, time travel, and mystery awaits.