Unknown to Penelope, her mother is marrying for security, not love. But when she finds two genies in an opal, she also finds being granted wishes is a battle of wills, hers and the genies'. Will her mother's wedding take place?
When a tour group arrives at Townes Downs, the Australian father-and-son guides recognise Penelope's opal as their ancestor's 'good luck charm' and they want it back. Bruce and Baz, however, prefer selfish Penelope for a master.
The genies try to trick Penelope into granting them their freedom but the plan goes quite wrong and the three end up trapped inside the opal with no one knowing where they (or the opal) are.
A trying day: Penelope tries to win a race without wishes, Bubbles tries convincing Diana he's changed, Conrad tries to get the opal, Scotland Yard tries to find Marcia then Otto and of course, the genies try to get freed.
Penelope, Lady Diana and Mossie are arrested by a Customs Officer when they return to England with 20 million pounds provided by the genies. That exact amount has just gone missing from the Royal Mint.
Bruce helped Otto and Conrad get the opal, but he only did it because he thought they would help him return to Australia. It didn't turn out like Bruce expected it would; instead the Von Meisters sold the opal for 25,000 pounds.
Lady Diana's wish is to visit Australia. Her wish is granted and they are back at Townes Downes. Penelope is furious. She decides to punish Lady Diana and Bruce. She wishes that Lady Diana and Otto would fall madly in love.
Bruce always misinterprets her wishes, so Penelope writes down her perfect wish. Everything turns out fine, Marcia is ugly, Penelope is perfect, and Lady Diana is rich. However, the two genies have the last laugh.
Conrad figures out that Bruce and Baz are magical genies, so he decides to work on Baz by taking him to a place where any kid would want to go, an amusement park. When Conrad takes the opal, Baz helps Penelope get it back.
Penelope wishes that she would be in England in time for Marcia's birthday party. When Penelope arrives in England, she finds out that she has a catch-up exam.
Identical twins give Otto and Conrad the idea to make a copy of the opal and swap it with Penelope's opal. With a real opal and two replicas, there is a lot opal rubbing, but not much magic.
Bruce manages to get the opal back to the cave. Penelope on the other hand convinces him not to leave. Later that day, Bruce and Diana share a passionate kiss.