When Bess Denyar, a successful doctor with an architect husband, an overbearing mother and twin thirteen year olds at a private school, finds out that she is adopted, she is stunned. Even more so when she is reunited with her birth parents. Wayne and Julie Wheeler, parents also to Amber, Kayne and Brianna, head up a drag racing team in the outer suburbs and are shocked and thrilled to discover the daughter they thought they had lost is now found.

When Wayne and Julie give Bess a 'Hot Lap' - a ride in a V8 Supercar, to make up for all the birthdays they've missed, Bess is shocked to discover that she is a natural behind the wheel of a very fast car. Convinced now that she is actually a "Wheeler", Bess sets about making herself as much like the rest of the Wheeler family as she can.

Bess arranges a lunch for her two mothers, Margaret and Julie, which ends in disaster when Julie, unaware of Bess' allergies, puts peanuts in the meal and Bess goes into anaphylactic shock.

While Bess is thrilled that her two families are coming together, when Danny finds out that Shawn and Edwina have skipped school and gone dirt bike riding, he freaks out, jumping to all sorts of wrong conclusions.