William takes the Magician's lost pendulum from Mary and, enthralled by its power, helps Morden travel from the past into the present. But he is unaware that Morden has brought a piece of the Black Gold with him, or of its dangerous ""negative energy"".

As the evil Black Gold spreads its negative energy throughout Golden Valley, the children become desperate for the Magician's help. But without his magic pendulum he seems stuck in the 17th century, until he remembers that there may be another way to travel through time to the present. Mary is horrified to discover that Mark, the object of her first crush, is a descendant of Matthew Morden.

With the Magician trapped in the dream world and fading, the children's only hope is to find his lost pendulum. Meanwhile, after William reveals Meg Lewis's role in forestalling the theme park's development, Meg is in grave danger.