Mr. Merlin teaches Zac how to use starsand, which changes things into other things, for a little while at least.
After the lesson, Mr. Merlin receives an invitation to a party and Zac discovers that Jessie Taylor, a beautiful pin-up girl will be at that party as well. He has a picture of her in his locker at school and he bets with a friend that he will get a picture of him and the girl. Zac begs Mr. Merlin to take him along to the party but when Mr. Merlin is called away on an emergency by Alex, Zac uses the starsand to change the name on the invitation, to change the car into a better one and to change his jeans into proper party clothing. At the party he and Leo get to talk to Jessie but when Mr. Merlin comes home and notices the missing invitation, he and Alex go to the party as well. Leo gets to dance with Alex while Mr. Merlin asks Zac whether he heeded his warning, to wash his hands after using the starsand and Zac realises he hasn't. All the people at the party, including Jessie, will return to the way they were shortly before the party. When Zac hears this he rushes to Jessie who tells him she was in the shower before the party. He lifts her up and jumps with her in the pool, just before her clothes disappear. He's now wearing his old jeans but manages to find a bathrobe for Jessie while other people, many now in underwear or nude as well, join them in the pool.
Mr. Merlin and Zac quickly leave the party and the next day, Zac's friend urges him to pay as he doesn't have any proof of his meeting with Jessie.
Just then she drives by, stops and thanks him for his rescue with the bathrobe, she return his sneaker and leaves Zac's friends very impressed with Zac.