What would you do if you found out you'd been raising another couple's child - and they've been raising yours?

Fourteen years ago, Kelsey and Raf Maccioni left hospital with their newborn daughter, Ammy. Days later, Shona and Nathan James welcomed the birth of their son, Zac.

The only thing the two couples have in common is the IVF clinic where their dreams came true. They are strangers to each other – for now.

Fast forward to April 2024 . . . Ammy has grown into a rebellious young woman, and Zac is a kind but introverted teenager.

Life may not be perfect for either family, but like everyone else they are muddling through.

Until Ammy takes a DNA test for a school project. At first the results are puzzling. Then disturbing. Then earth-shattering - when the IVF clinic admits a terrible mistake.